(1):

(v. i.) To exist actually, or in the world of fact; to have ex/stence.

(2):

(v. i.) To exist in a certain manner or relation, - whether as a reality or as a product of thought; to exist as the subject of a certain predicate, that is, as having a certain attribute, or as belonging to a certain sort, or as identical with what is specified, - a word or words for the predicate being annexed; as, to be happy; to be here; to be large, or strong; to be an animal; to be a hero; to be a nonentity; three and two are five; annihilation is the cessation of existence; that is the man.

(3):

(v. i.) To take place; to happen; as, the meeting was on Thursday.

(4):

(v. i.) To signify; to represent or symbolize; to answer to.