\ ˈbās How to pronounce base (audio) \
plural bases\ ˈbā-​səz How to pronounce bases (audio) \

Definition of base

 (Entry 1 of 4)

1a : the bottom of something considered as its support : foundation the base of the mountain the lamp's heavy base
b biology : that part of a bodily organ by which it is attached to another more central structure of the organism the base of the thumb
c architecture
(1) : the lower part of a wall, pier, or column considered as a separate architectural feature
(2) : the lower part of a complete architectural design (as of a monument)
d mathematics
(1) : a side or face (see face entry 1 sense 5a(5)) of a geometrical figure from which an altitude (see altitude sense 1c(1)) can be constructed especially : a side or face on which the figure stands the base of a triangle
(2) : the length of a base determining the triangle's base
2a : a main ingredient paint having a latex base
b : a supporting or carrying ingredient (as of a medicine)
c : a first or bottom layer of something on which other elements are added Overnight, Utah's famous snow has freshly blanketed both runs, adding to a solid base of three feet …— Abby Carroll
3a : the fundamental part of something : groundwork, basis the book's theoretical base her broad base of knowledge
b : something (as a group of people) that reliably provides support (such as for a business or political candidate) usually singularefforts to expand their customer basethe band's fan baseBut I do believe that that's a very sore point with many Democrats and could be used to energize their base.— John McCain
c Marxism : the economic factors on which all legal, social, and political relations are formed
4a : the starting point or line for an action or undertaking plans to make this city his base of operation— J. A. Loftus
c : a center or area of operations The company has its base in London. : such as
(1) : a permanent military installation a naval base The troops were ordered back to base.
(2) : the place from which a military force draws supplies
(3) : a place where military operations begin
d linguistics : root sense 6 "Leave" is the base of the verb "left."
e mathematics
(1) : a number (such as 5 in 56.44 or 57) that is raised to a power (see power entry 1 sense 5a) especially : the number that when raised to a power equal to the logarithm of a number yields the number itself The logarithm of 100 to the base 10 is 2 since 102 = 100.
(2) : a number equal to the number of units in a given digit's place (see place entry 1 sense 8) that for a given system of writing numbers is required to give the numeral 1 in the next higher place The decimal system uses a base of 10. also : such a system of writing numbers using an indicated base Convert from base 10 to base 2.
(3) : a number that is multiplied by a rate or of which a percentage or fraction is calculated To find the interest on $90 at 10 percent multiply the base 90 by .10.
5a : any one of the four stations at the corners of a baseball or softball infield allowing the batter to reach base
b in various games : the starting place or goal
c : a point to be considered His opening remarks touched every base.
6 chemistry
a : any of various typically water-soluble and bitter tasting compounds that in solution have a pH greater than 7, are capable of reacting with an acid to form a salt, and are molecules or ions able to take up a proton from an acid or able to give up an unshared pair of electrons to an acid
b : any of the five purine or pyrimidine bases of DNA and RNA that include cytosine, guanine, adenine, thymine, and uracil
7 finance : a price level at which a security (see security sense 3) previously declining in price resists further decline
8 heraldry : the lower part of a heraldic field (see field entry 1 sense 3c)
9 linguistics : the part of a transformational grammar that consists of rules and a lexicon and generates the deep structures of a language
10 : an electrode that modulates the current flowing through a bipolar junction transistor according to the voltage applied to the electrode This gate, which is called a grid in a tube and a base in a transistor, enables a small "controlling" voltage to turn on and off a much larger voltage between the cathode and the anode.— Thom Hartmann — compare gate entry 1 sense 5b
cover all the bases or less commonly cover every base or have (all) one's bases covered
: to do or include everything that needs to be done or included : to fulfill all requirements or necessities The well rounded menu covers all the bases—pork or duck breast and always a grilled chicken with complementary sauces and relishes …— Caroline Bates In other words, we need to cover every base. Too often, something is remembered at the last minute and we find ourselves waiting for the stores to open on sale day so we can purchase a much-needed item.— Sue Story In your e-mail, let the company know that, for their convenience, you're e-mailing the resume and letter, but that the original documents will arrive by postal service. This way you've got all your bases covered.— Peter Post
off base
1 : wrong, mistaken Estimates were way off base.
2 : unawares caught off base by the charges
touch all the bases or less commonly touch every base
1 : to mention every subject that needs to be considered a speech that touches all the bases
2 : to do or include everything that needs to be done or included : to fulfill all requirements or necessities need to touch all the bases when applying for a mortgage The owner of the Utah Stars is in Salt Lake City, working 24 hours a day in an effort to touch every base to keep his club in Utah's capital city.— Dan Pattison


based; basing

Definition of base (Entry 2 of 4)

transitive verb

1 : to find a foundation or basis for : to find a base (see base entry 1 sense 3a) for usually used with on or uponbase an opinion on faulty informationa story based upon real-life events
2 : to make, form, or serve as a base for … great roots based the tree columns …— George Macdonald the company is based in London clients who are based out of their homes

Definition of base (Entry 3 of 4)

1a : lacking or indicating the lack of higher qualities of mind or spirit : ignoble seemed a base betrayal of idealism— L. M. Sears appealing to a person's baser instincts
b : lacking higher values : degrading a drab base way of life
2a : being of comparatively low value and having relatively inferior properties (such as lack of resistance to corrosion) a base metal such as iron — compare noble entry 1
b : containing a larger than usual proportion of base metals base silver denarii
3 feudalism
a : resembling a villein : servile a base tenant
b : held by villenage base tenure
4 archaic : of little height … the cedar stoops not to the base shrub's foot …— Shakespeare
5 archaic : baseborn base in kind and born to be a slave.— William Cowper
6 obsolete : low in place or position … fall to the base earth from the firmament!— Shakespeare
7 obsolete : bass

Definition of base (Entry 4 of 4)

1 : constituting or serving as a base This situation is frequently encountered by seaplane pilots in northern Canada who must fly over lakes and tundra to a base camp located on a river.— Alan Lopez
2 : of the simplest or most basic design or form : having the form of something before upgrades or customization This GTO's 350-hp, 5.7-liter V8 is the same that's used in the base Corvette, and it produces the power and throaty exhaust sound of a classic muscle car.Consumer Reports

Illustration of base

Illustration of base


base of a column: 1 upper torus, 2 scotia, 3 lower torus, 4 plinth, 5 shaft, 6 fillets

In the meaning defined above

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Other Words from base


baseless \ ˈbā-​sləs How to pronounce baseless (audio) \ adjective

Adjective (1)

basely adverb
baseness noun

Choose the Right Synonym for base

Adjective (1)

base, low, vile mean deserving of contempt because of the absence of higher values. base stresses the ignoble and may suggest cruelty, treachery, greed, or grossness. base motives low may connote crafty cunning, vulgarity, or immorality and regularly implies an outraging of one's sense of decency or propriety. refused to listen to such low talk vile, the strongest of these words, tends to suggest disgusting depravity or filth. a vile remark

Examples of base in a Sentence

Noun the firm belief that complete trust between husband and wife is the base of any successful marriage the army's base of attack was kept top secret until the battle began Verb They are going to base their new company in Seattle. The company has based itself in London. Our tour group based itself in a hotel in the heart of the city. Adjective (1) Iron is a base metal. a base and sneaky act that is a clear violation of international law
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Recent Examples on the Web: Noun Local media reported that the Okinawan assembly adopted a resolution Friday protesting the U.S. military's lack of transparency about its outbreak on base. Mari Yamaguchi, Anchorage Daily News, "Dozens of US Marines in Japan’s Okinawa get coronavirus," 11 July 2020 Local media reported that the Okinawan assembly adopted a resolution Friday protesting the U.S. military’s lack of transparency about its outbreak on base, and that local officials were considering demanding shutdowns of Futenma and Camp Hansen. Washington Post, "Dozens of US Marines in Japan’s Okinawa get coronavirus," 11 July 2020 They are expected to spend five to 10 days on the base. Barbara Starr, CNN, "Army launches civilian review of Fort Hood following Vanessa Guillen's killing," 10 July 2020 His on-base percentage was .304 and his slugging percentage .384, both well under the standards needed to be an everyday player. Anthony Fenech, Detroit Free Press, "Detroit Tigers' Harold Castro keeps on hitting. So how will he fit in this lineup?," 10 July 2020 Following a two-hour interaction with police on the base, Capt. Ashley Shaffer, USA TODAY, "It's not US, it's WHO," 7 July 2020 Inscriptions on the base are filled with tributes to Stuart, who was fatally wounded by a Union soldier and died at age 31 on May 12, 1864. Time, "Richmond Removes Statue of Confederate Gen. J.E.B. Stuart as Crowd Cheers," 7 July 2020 Akiyama is the wild-card of the group, but his on-base percentage was .385 or higher for his last five seasons in Japan. Tyler Dragon, The Enquirer, "Professional sports are back. Here's what fans have to look forward to in Cincinnati.," 6 July 2020 Joining a program that made four straight College World Series appearances from 2014 through 2017, Brown started his first 16 games, hitting .279 with a .405 on-base percentage. Greg Luca,, "Reagan product Porter Brown relishing opportunity with Flying Chanclas de San Antonio," 4 July 2020 Recent Examples on the Web: Verb An agreement to base 1,000 troops in Poland awaits the signing of a defense cooperation agreement by Warsaw. Abraham Mahshie, Washington Examiner, "Pentagon to remove 12,000 troops from Germany to meet Trump demand," 29 July 2020 But don’t look at Mahomes’ extension as the one to base a potential Mayfield extension, unless Mayfield comes out this year, wins the MVP and a Super Bowl. Dan Labbe, cleveland, "Patrick Mahomes’ extension doesn’t directly affect Baker Mayfield, but some upcoming quarterback contracts might," 6 July 2020 Last August, the government passed regulations for patented drugs that would base Canadian prices on those from a group of countries with lower prices than a benchmark group now used to set ceilings. Ed Silverman, STAT, "Canadian court upholds most of a controversial new rule for controlling excessive drug prices," 30 June 2020 Salaries of executives and managers were restored to base starting next month after going to reduced levels in April. Sarah Hauer, Milwaukee Journal Sentinel, "Briggs & Stratton is moving production from its facility in Wauwatosa to New York," 26 June 2020 Kids can base the new monikers on mythology, cartoon characters, or even their friends. Avery Hurt, National Geographic, "Why getting your kid’s head in the clouds is a good thing," 18 June 2020 Duda, who faces a tough reelection vote Sunday, was hoping to bring home a commitment from Trump to base 1,000 U.S. troops in Poland in addition to the armored brigade of 4,500 that rotates in and out of the country. Jamie Mcintyre, Washington Examiner, "Polish leader leaves with no new commitment of US troops as Pentagon shifts focus away from Europe and toward countering China," 25 June 2020 If no American will do the job, then the only comparable work on which to base a prevailing wage is the labor performed either by other guest workers or by undocumented workers. Timothy Noah, The New Republic, "How to Fix America’s Broken Guest-Worker System," 24 June 2020 Little also signed a bill, which sponsors titled the Fairness in Women’s Sports Act, that requires public school and college sports teams to base participation on an athlete’s gender at birth. Bob Egelko,, "California says no state-funded travel to Idaho — 12th state cited for gender discrimination," 22 June 2020 Recent Examples on the Web: Adjective The 33-year-old Smoak had no extra-base hits and a .238 average in 21 Cactus League at-bats before spring training was scrapped. Todd Rosiak, Milwaukee Journal Sentinel, "Justin Smoak trying his best to make sense of a changed game in the COVID-19 era," 11 July 2020 This is a guy who had 202 extra-base hits in 488 minor-league games. Jeff Seidel, Detroit Free Press, "Detroit Tigers' Christin Stewart knows what he needs to do: 'Put the ball in the seats'," 10 July 2020 Second baseman Kody Clemens, who hit .238 with 42 extra-base hits in 115 games in Class A Lakeland, was considered an option. Anthony Fenech, Detroit Free Press, "Here's why Spencer Torkelson isn't on the Detroit Tigers' 60-man player list — yet," 28 June 2020 He is paid a base salary of $735,000 with an additional maximum of $281,137.50 available in team performance bonuses. Nathan Baird, cleveland, "Iowa parts ways with strength coach Chris Doyle, begins investigation into his comments to black players," 15 June 2020 City records show that Lascko, who works for the DOC’s Transportation Division, has a base salary of $82,292. Fox News, "NYC corrections officer suspended over sick George Floyd parody photo," 7 June 2020 Katy’s Kailey Wyckoff balanced 57 strikeouts with 13 extra-base hits and 18 runs as the leadoff hitter. Jack Marrion, Houston Chronicle, "Katy softball players produced in shortened season," 6 June 2020 The base salary for a California legislator is at $114,877, which was the highest in the nation until New York bumped its lawmakers' commission up to $120,000 in January. Mica Soellner, Washington Examiner, "California elected officials face no pay cuts despite economic turmoil brought by coronavirus pandemic," 28 May 2020 Smith’s one-year contract with the Cowboys is worth up to $4 million between a $2 million base salary and $2 million in potential incentives. Dallas News, "Storytime with Aldon Smith: Cowboys DE volunteers to read for kids," 26 May 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'base.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of base


14th century, in the meaning defined at sense 1c(1)


1587, in the meaning defined at sense 2

Adjective (1)

14th century, in the meaning defined at sense 4

Adjective (2)

1734, in the meaning defined at sense 1

History and Etymology for base


Middle English, from Anglo-French, from Latin basis, from Greek, step, base, from bainein to go — more at come


verbal derivative of base entry 1

Adjective (1)

Middle English bas, from Anglo-French, from Late Latin bassus fat, short, low

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Time Traveler for base

Time Traveler

The first known use of base was in the 14th century

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Statistics for base

Last Updated

2 Aug 2020

Cite this Entry

“Base.” Dictionary, Merriam-Webster, Accessed 6 Aug. 2020.

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More Definitions for base


How to pronounce base (audio)

English Language Learners Definition of base

 (Entry 1 of 2)

: the bottom or lowest part of something : the part on which something rests or is supported
: something (such as a group of people or things) that provides support for a place, business, etc.
: a main ingredient to which other things are added to make something



English Language Learners Definition of base (Entry 2 of 2)

: to have a particular place as the main place where a person works or lives or where a business operates


\ ˈbās How to pronounce base (audio) \

Kids Definition of base

 (Entry 1 of 3)

1 : a thing or a part on which something rests : bottom, foundation the base of a statue the base of the mountain
2 : a starting place or goal in various games
3 : any of the four stations a runner in baseball must touch in order to score
4 : the main place or starting place of an action or operation The company's base is in New York.
5 : a place where a military force keeps its supplies or from which it starts its operations an air force base
6 : a line or surface of a geometric figure upon which an altitude is or is thought to be constructed base of a triangle
7 : the main substance in a mixture
8 : a number with reference to which a system of numbers is constructed
9 : a chemical substance (as lime or ammonia) that reacts with an acid to form a salt and turns red litmus paper blue


based; basing

Kids Definition of base (Entry 2 of 3)

: to use as a main place of operation or action The company is based in Ohio.
base on or base upon
: to make or form from a starting point It's based on a true story.
baser; basest

Kids Definition of base (Entry 3 of 3)

1 : of low value and not very good in some ways base metals
2 : not honorable “I'll appeal to his baser instincts, of which he has plenty.”— E. B. White, Charlotte's Web


\ ˈbās How to pronounce base (audio) \
plural bases\ ˈbā-​səz How to pronounce bases (audio) \

Medical Definition of base

1 : that portion of a bodily organ or part by which it is attached to another more central structure of the organism the base of the thumb
2a : the usually inactive ingredient of a preparation serving as the vehicle for the active medicinal preparation the fatty base of an ointment
b : the chief active ingredient of a preparation

called also basis

3a : any of various typically water-soluble and bitter tasting compounds that in solution have a pH greater than 7, are capable of reacting with an acid to form a salt, and are molecules or ions able to take up a proton from an acid or are substances able to give up an unshared pair of electrons to an acid — compare alkali
b : any of the five purine or pyrimidine bases of DNA and RNA that include cytosine, guanine, adenine, thymine, and uracil

Other Words from base

based \ ˈbāst How to pronounce based (audio) \ adjective

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More from Merriam-Webster on base

Thesaurus: All synonyms and antonyms for base

Rhyming Dictionary: Words that rhyme with base

Spanish Central: Translation of base

Nglish: Translation of base for Spanish Speakers

Britannica English: Translation of base for Arabic Speakers Encyclopedia article about base

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