Real Dictionary

nibble
Nibbles are small snacks such as biscuits, crisps, and nuts that are often offered to you at parties.
verb: If one thing nibbles at another, it gradually affects, harms, or destroys it.
verb: If you nibble food, you eat it by biting very small pieces of it, for example because you are not very hungry.
verb: If you nibble something, you bite it very gently.
verb: When an animal nibbles something, it takes small bites of it quickly and repeatedly.

nibble in American English
to eat (food) with quick bites, taking only a small amount at a time, as a mouse does
to take small, cautious, or gentle bites
intransitive verb: to bite off small bits
transitive verb: to bite off small bits of (something)

nibble in British English
noun: a small mouthful
verb: (esp of animals, such as mice) to take small repeated bites (of)