Is be a prefix as in befriend?

You're close! "Be" is not a prefix in "befriend", but it is part of the verb itself.

* Befriend is a single, combined word, and "be" is not a separate unit added to the front.

* Prefixes are added to the beginning of a word to change its meaning. Examples of prefixes include "un-" (undo), "re-" (rewrite), and "pre-" (pre-game).

So, while "be" often signifies a state of being or action, it doesn't function as a prefix in "befriend".