Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


adjective con·stant \ˈkän(t)-stənt\

Simple Definition of constant

  • : happening all the time or very often over a period of time

  • : staying the same : not changing

  • : always loyal

Source: Merriam-Webster's Learner's Dictionary

Full Definition of constant

  1. 1 :  marked by firm steadfast resolution or faithfulness :  exhibiting constancy of mind or attachment <a constant friend>

  2. 2 :  invariable, uniform <a constant flow>

  3. 3 :  continually occurring or recurring :  regular <a constant annoyance>

constantly adverb

Examples of constant in a sentence

  1. He suffers from constant headaches.

  2. Her constant chatter was a nuisance.

  3. The house is in constant need of repairs.

  4. The scar serves as a constant reminder of the accident.

  5. a problem demanding constant attention

  6. The equipment should be stored at a constant temperature.

  7. He kept the car's speed constant.

  8. She has struggled to maintain a constant weight.

  9. They remained constant friends throughout their lives.

Origin of constant

Middle English, from Middle French, from Latin constant-, constans, from present participle of constare to stand firm, be consistent, from com- + stare to stand — more at stand

First Known Use: 14th century

Synonym Discussion of constant

faithful, loyal, constant, staunch, steadfast, resolute mean firm in adherence to whatever one owes allegiance. faithful implies unswerving adherence to a person or thing or to the oath or promise by which a tie was contracted <faithful to her promise>. loyal implies a firm resistance to any temptation to desert or betray <remained loyal to the czar>. constant stresses continuing firmness of emotional attachment without necessarily implying strict obedience to promises or vows <constant friends>. staunch suggests fortitude and resolution in adherence and imperviousness to influences that would weaken it <a staunch defender of free speech>. steadfast implies a steady and unwavering course in love, allegiance, or conviction <steadfast in their support>. resolute implies firm determination to adhere to a cause or purpose <a resolute ally>.

continual, continuous, constant, incessant, perpetual, perennial mean characterized by continued occurrence or recurrence. continual often implies a close prolonged succession or recurrence <continual showers the whole weekend>. continuous usually implies an uninterrupted flow or spatial extension <football's oldest continuous rivalry>. constant implies uniform or persistent occurrence or recurrence <lived in constant pain>. incessant implies ceaseless or uninterrupted activity <annoyed by the incessant quarreling>. perpetual suggests unfailing repetition or lasting duration <a land of perpetual snowfall>. perennial implies enduring existence often through constant renewal <a perennial source of controversy>.



noun con·stant

Simple Definition of constant

  • : something that stays the same : something that does not change

  • : a quantity or number whose value does not change

Source: Merriam-Webster's Learner's Dictionary

Full Definition of constant

  1. :  something invariable or unchanging: as a :  a number that has a fixed value in a given situation or universally or that is characteristic of some substance or instrument b :  a number that is assumed not to change value in a given mathematical discussion c :  a term in logic with a fixed designation

Examples of constant in a sentence

  1. Her job was the one constant in her life.


First Known Use of constant


CONSTANT Defined for Kids


adjective con·stant \ˈkän-stənt\

Definition of constant for Students

  1. 1 :  remaining steady and unchanged <a constant temperature>

  2. 2 :  occurring continuously or following one after another <constant headaches>

  3. 3 :  always faithful and true <constant friends>

constantly adverb

Seen and Heard

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


a smart aleck

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which of these is a synonym of unctuous?

oily prompt angry maudlin
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.