Definition of is

 (Entry 1 of 4)

present tense third-person singular of be

dialectal present tense first-person and third-person singular of be

dialectal present tense plural of be


abbreviation (1)

Definition of is (Entry 2 of 4)

island; isle


abbreviation (2)

Definition of IS (Entry 3 of 4)

information system
variants: or iso-

Definition of is- (Entry 4 of 4)

1 : equal : homogeneous : uniform isentropic
2 : isomeric isocyanate
3 : for or from different individuals of the same species isoagglutinin

History and Etymology for is

Middle English, from Old English; akin to Old High German ist is (from sīn to be), Latin est (from esse to be), Greek esti (from einai to be)

Combining form

Late Latin, from Greek, from isos equal

Keep scrolling for more

Keep scrolling for more

More Definitions for is


Kids Definition of is

present tense third person singular of be

Keep scrolling for more

More from Merriam-Webster on is

Rhyming Dictionary: Words that rhyme with is

Spanish Central: Translation of is

Nglish: Translation of is for Spanish Speakers

Britannica English: Translation of is for Arabic Speakers

Comments on is

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


to gather or build up little by little

Get Word of the Day daily email!

Test Your Vocabulary

Homophone Quiz

  • three-bears-two-of-them-look-like-theyre-whispering-to-a-third-bear-who-looks-chuffed-to-be-the-center-of-attention
  • In order to judge how people felt, the senator's office hired a firm to take a ______.
Spell It

Can you spell these 10 commonly misspelled words?

Syn City

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


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!