noun, often attributive
base·​line | \ˈbās-ˌlīn \

Definition of baseline 

1 : a line serving as a basis especially : one of known measure or position used (as in surveying or navigation) to calculate or locate something

2a : either of the lines on a baseball field that lead from home plate to first base and third base and are extended into the outfield as foul lines

b : basepath

3 : a boundary line at either end of a court (as in tennis or basketball)

4 : a usually initial set of critical observations or data used for comparison or a control

5 : a starting point the baseline of this discussion

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Examples of baseline in a Sentence

The experiment is meant only to provide a baseline for other studies. any year or event we use as the baseline for the Renaissance is going to be at least somewhat arbitrary

Recent Examples on the Web

Scientists want to develop a baseline of knowledge about the sand lance to see if their habitat is changing. Katherine Long, The Seattle Times, "In a five-person submarine, scientists in Friday Harbor unravel the mysteries of the Salish Sea," 16 Sep. 2018 The whole point of FMVSS exemptions is to balance the need for the development of transportation innovation with an accepted baseline of safety. WSJ, "Mr. Nader Misses the Mark on Driverless Cars," 30 Aug. 2018 If the schedule holds, the F-35 will be baseline operational 18 years after it was selected over Boeing's X-32, and 23 years after the program began. Eric Tegler, Popular Mechanics, "WTF-35: How the Joint Strike Fighter Got to Be Such a Mess," 27 July 2018 New York Car ownership baseline: $7,237 Parking: $5,395 Congestion: $2,960 Parking pain: $3,334 Total cost of driving in New York: $18,926 2. Kirsten Korosec, Fortune, "The 10 Most Expensive Cities To Own a Car," 10 Apr. 2018 The two younger Mary Pages set the baseline beautifully. Jesse Green, New York Times, "Review: ‘Mary Page Marlowe’ Lives an Ordinary, Extraordinary Life," 12 July 2018 There is no sign that Kim Jong Un is contemplating what nuclear experts say has to be the first step: a full disclosure of his weapons program, to create a baseline for future inspection and verification, fundamental to any arms-control agreement. NBC News, "North Korea shatters Trump's boastful assurances of an easy path to denuclearization," 7 July 2018 In the same way, there’s a chance the California standard will become the baseline for Internet privacy when the law takes effect on Jan. 1, 2020. Hiawatha Bray,, "Calif.’s Net privacy law gives consumers more clout, and Big Tech may be just fine with that," 1 July 2018 And to create a baseline for the other two categories, a panel of moms had to unanimously agree on whether the cry was either hungry or fussy. CBS News, "ChatterBaby app could help parents figure out why their baby is crying," 28 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'baseline.' 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 baseline

circa 1556, in the meaning defined at sense 1

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Statistics for baseline

Last Updated

29 Nov 2018

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Time Traveler for baseline

The first known use of baseline was circa 1556

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More Definitions for baseline



English Language Learners Definition of baseline

: information that is used as a starting point by which to compare other information

: a line at either end of the playing area in games like basketball and tennis

baseball : either one of the lines that lead from home plate to first base and third base


base·​line | \ˈbā-ˌslīn \

Medical Definition of baseline 

: a set of critical observations or data used for comparison or a control

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Comments on baseline

What made you want to look up baseline? Please tell us where you read or heard it (including the quote, if possible).


to move with a clumsy heavy tread

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