1. [n]  gentle biting
2. [n]  a small byte
3. [v]  eat lightly; "She just nibbles at her food"
4. [v]  eat intermittently; take small bites of; "He pieced at the sandwich all morning"; "She never eats a full meal--she just picks at the food"
5. [v]  bite off very small pieces; "She nibbled on her cracker"

1. \Nib"ble\, v. t. [imp. & p. p. {Nibbled}; p. pr. & vb. n.
   {Nibbling}.] [Cf. {Nip}.]
   To bite by little at a time; to seize gently with the mouth;
   to eat slowly or in small bits.
         Thy turfy mountains, where live nibbling sheep. --Shak.
   

2. \Nib"ble\, v. t.
   To bite upon something gently or cautiously; to eat a little
   of a thing, as by taking small bits cautiously; as, fishes
   nibble at the bait.
         Instead of returning a full answer to my book, he
         manifestly falls a-nibbling at one single passage.
                                                  --Tillotson.
   

3. \Nib"ble\, n.
   A small or cautious bite.
   

/nib'l/ (US "nybble", by analogy with "bite" -> "byte") Half a byte. Since a byte is nearly always eight bits, a nibble is nearly always four bits (and can therefore be represented by one hex digit).

Other size nibbles have existed, for example the BBC Microcomputer disk file system used eleven bit sector numbers which were described as one byte (eight bits) and a nibble (three bits).

Compare crumb, tayste, dynner; see also bit, nickle, deckle.

The spelling "nybble" is uncommon in Commonwealth Hackish as British orthography suggests the pronunciation /ni:'bl/.