Real Dictionary

barb
countable noun: A barb is a sharp curved point near the end of an arrow or fish-hook which makes it difficult to pull out.
countable noun: A barb is an unkind remark meant as a criticism of someone or something.

barb in American English 1
a thin, somewhat beardlike growth near the mouth of certain animals, as the barbel of a fish
to provide with a barb
noun: a point or pointed part projecting backward from a main point, as of a fishhook or arrowhead
transitive verb: to furnish with a barb or barbs

barb in American English 2
a horse of a breed native to N Africa, noted for speed and strength
noun: one of a breed of horses raised originally in Barbary

barb in American English 3
noun: barbiturate

BARB in British English
noun acronym for: Broadcasters' Audience Research Board

barb in British English 1
noun: a subsidiary point facing in the opposite direction to the main point of a fish-hook, harpoon, arrow, etc, intended to make extraction difficult
verb: to provide with a barb or barbs

barb in British English 2
noun: a breed of horse of North African origin, similar to the Arab but less spirited

barb in British English 3
noun: a black kelpie