a shortened form of a word or group of words, with the omitted letters often replaced in written English by an apostrophe, as e'er for ever, isn't for is not, dep't for department.
Physiology. the change in a muscle by which it becomes thickened and shortened.
a restriction or withdrawal, as of currency or of funds available as call money.
a decrease in economic and industrial activity (opposed to expansion).
Origin of contraction
1375–1425;late Middle English (< Middle French) < Latincontractiōn- (stem of contractiō), equivalent to contract(us) drawn together, past participle of contrahere (see contract) + -iōn--ion
Related formscon·trac·tion·al, adjectivenon·con·trac·tion, nouno·ver·con·trac·tion, nounre·con·trac·tion, noun
Contractions such as isn't, couldn't, can't, weren't, he'll, they're occur chiefly, although not exclusively, in informal speech and writing. They are common in personal letters, business letters, journalism, and fiction; they are rare in scientific and scholarly writing. Contractions occur in formal writing mainly as representations of speech.
late 14c., "action of making a contract" (especially of marriage), also "action of shrinking or shortening," from Old French contraction (13c.), or directly from Latin contractionem (nominative contractio), noun of action from past participle stem of contrahere (see contract (n.)). Meaning "action of acquiring (a disease) is from c.1600. Grammatical sense is from 1706; meaning "a contracted word or words" is from 1755. Contractions of the uterus in labor of childbirth attested from 1962.