(past first & third singular was; second singular were; plural were; past subjunctive were; past part been; present part being; present first singular am; second singular are; third singular is; plural are; present subjunctive be)
Etymology: Middle English, from Old English bēon; akin to Old High German bim am, Latin fui I have been, futurus about to be, fieri to become, be done, Greek phynai to be born, be by nature, phyein to produce
Date: before 12th century
a. to equal in meaning ; have the same connotation as ; symbolize <God is love> <January is the first month> <let x be 10> b. to have identity with <the first person I met was my brother> c. to constitute the same class as d. to have a specified qualification or characterization <the leaves are green> e. to belong to the class of <the fish is a trout> — used regularly in senses 1a through 1e as the copula of simple predication 2. a. to have an objective existence ; have reality or actuality ; live <I think, therefore I am> <once upon a time there was a knight> b. to have, maintain, or occupy a place, situation, or position <the book is on the table> c. to remain unmolested, undisturbed, or uninterrupted — used only in infinitive form <let him be> d. to take place ; occur <the concert was last night> e. to come or go <has already been and gone> <has never been to the circus> f. archaic belong, befall verbal auxiliary 1. — used with the past participle of transitive verbs as a passive-voice auxiliary <the money was found> <the house is being built> 2. — used as the auxiliary of the present participle in progressive tenses expressing continuous action <he is reading> <I have been sleeping> 3. — used with the past participle of some intransitive verbs as an auxiliary forming archaic perfect tenses < 4. — used with the infinitive with to to express futurity, arrangement in advance, or obligation <I am to interview him today> <she was to become famous>
New Collegiate Dictionary. 2001.