Source : Webster's Revised Unabridged Dictionary (1913)

Be- \Be-\ [AS. be, and in accented form b[=i], akin to OS. be
   and b[=i], OHG. bi, pi, and p[=i], MHG. be and b[=i], G. be
   and bei, Goth. bi, and perh. Gr. ? about (cf. AS. bese['o]n
   to look about). [root]203. Cf. {By}, {Amb-}.]
   A prefix, originally the same word as by; joined with verbs,
   it serves:
   (a) To intensify the meaning; as, bespatter, bestir.
   (b) To render an intransitive verb transitive; as, befall (to
       fall upon); bespeak (to speak for).
   (c) To make the action of a verb particular or definite; as,
       beget (to get as offspring); beset (to set around).

   Note: It is joined with certain substantives, and a few
         adjectives, to form verbs; as, bedew, befriend,
         benight, besot; belate (to make late); belittle (to
         make little). It also occurs in certain nouns, adverbs,
         and prepositions, often with something of the force of
         the preposition by, or about; as, belief (believe),
         behalf, bequest (bequeath); because, before, beneath,
         beside, between. In some words the original force of be
         is obscured or lost; as, in become, begin, behave,
         behoove, belong.