be (v.)

Old English beon, beom, bion "be, exist, come to be, become, happen," from Proto-Germanic *biju- "I am, I will be." This "b-root" is from PIE root *bheue- "to be, exist, grow," and in addition to the words in English it yielded German present first and second person singular (bin, bist, from Old High German bim "I am," bist "thou art"), Latin perfective tenses of esse (fui "I was," etc.), Old Church Slavonic byti "be," Greek phu- "become," Old Irish bi'u "I am," Lithuanian būti "to be," Russian byt' "to be," etc.

The modern verb to be in its entirety represents the merger of two once-distinct verbs, the "b-root" represented by be and the am/was verb, which was itself a conglomerate. Roger Lass ("Old English") describes the verb as "a collection of semantically related paradigm fragments," while Weekley calls it "an accidental conglomeration from the different Old English dial[ect]s." It is the most irregular verb in Modern English and the most common. Collective in all Germanic languages, it has eight different forms in Modern English:

BE (infinitive, subjunctive, imperative); AM (present 1st person singular); ARE (present 2nd person singular and all plural); IS (present 3rd person singular); WAS (past 1st and 3rd persons singular); WERE (past 2nd person singular, all plural; subjunctive); BEING (progressive & present participle; gerund); BEEN (perfect participle).

The paradigm in Old English was: eom, beo (present 1st person singular); eart, bist (present 2nd person singular); is, bið (present 3rd person singular);  sind, sindon, beoð (present plural in all persons); wæs (past 1st and 3rd person singular); wære (past 2nd person singular); wæron (past plural in all persons); wære (singular subjunctive preterit); wæren (plural subjunctive preterit).

The "b-root" had no past tense in Old English, but often served as future tense of am/was. In 13c. it took the place of the infinitive, participle and imperative forms of am/was. Later its plural forms (we beth, ye ben, they be) became standard in Middle English and it made inroads into the singular (I be, thou beest, he beth), but forms of are claimed this turf in the 1500s and replaced be in the plural. For the origin and evolution of the am/was branches of this tangle, see am and was.

That but this blow Might be the be all, and the end all. ["Macbeth" I.vii.5]

updated on February 01, 2018

Definitions of be from WordNet
be (v.)
have the quality of being; (copula, used with an adjective or a predicate noun);
John is rich
be (v.)
be identical to; be someone or something;
The president of the company is John Smith
be (v.)
occupy a certain position or area; be somewhere;
Where is my umbrella?
The toolshed is in the back
be (v.)
have an existence, be extant;
Synonyms: exist
be (v.)
happen, occur, take place; "I lost my wallet; this was during the visit to my parents' house";
There was a lot of noise in the kitchen
There were two hundred people at his funeral
be (v.)
be identical or equivalent to;
Synonyms: equal
be (v.)
form or compose;
The stone wall was the backdrop for the performance
Synonyms: constitute / represent / make up / comprise
be (v.)
work in a specific place, with a specific subject, or in a specific function;
She is our resident philosopher
Synonyms: follow
be (v.)
represent, as of a character on stage;
Derek Jacobi was Hamlet
Synonyms: embody / personify
be (v.)
spend or use time;
I may be an hour
be (v.)
have life, be alive;
Our great leader is no more
Synonyms: live
be (v.)
to remain unmolested, undisturbed, or uninterrupted -- used only in infinitive form;
let her be
be (v.)
be priced at;
Synonyms: cost
Be (n.)
a light strong brittle grey toxic bivalent metallic element;
Synonyms: beryllium / glucinium / atomic number "
Etymologies are not definitions. From, not affiliated with etymonline.