Definition of be:

• To exist; to have a real state or existence; to be fixed; to be made to be; to become; to remain. Let be, to omit, or let alone.
• Infin. of the verb am, denoting to exist, to become, to remain; used in hypothetical and secondary propositions- as " If I be," " If thou be:".
• A prefix, signifying to make. When be is prefixed to a noun, the noun becomes a verb- thus, calm and friend are nouns, but becalm and befriend are verbs: be prefixed to a verb signifies about, over, for- thus, speak and think become bespeak and bethink: be in a preposition, an adverb, or a conjunction, has the force of by or in- thus.
• Saxon prefix to make, about, for, over, by, & c.