The Collaborative International Dictionary of English v.0.48:

Chunk \Chunk\ (ch[u^][ng]k), n. [Cf. Chump.]
   A short, thick piece of anything. [Colloq. U. S. & Prov.
   Eng.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

chunk
    n 1: a compact mass; "a ball of mud caught him on the shoulder"
         [syn: ball, clod, glob, lump, clump, chunk]
    2: a substantial amount; "we won a chunk of money"
    v 1: put together indiscriminately; "lump together all the
         applicants" [syn: lump, chunk]
    2: group or chunk together in a certain order or place side by
       side [syn: collocate, lump, chunk]

Moby Thesaurus II by Grady Ward, 1.0:

161 Moby Thesaurus words for "chunk":
   accumulation, acervation, agglomerate, agglomeration, aggregate,
   aggregation, allotment, allowance, amassment, amount, ante, batch,
   bet, big end, bigger half, bit, bite, block, book, bowl, budget,
   bulk, bunch, butt, cast, change of pace, change-up, chip, chuck,
   clip, clipping, clod, clump, clutch, collop, commission, congeries,
   conglobation, conglomerate, conglomeration, contingent, count,
   crumb, cumulation, curve, cut, cutting, deal, destiny, dividend,
   dole, dollop, dose, downcurve, end, equal share, fastball, fate,
   fling, flip, forward pass, fragment, gathering, glomeration, gob,
   gobbet, group, half, halver, handbook, hazard, heap, heave,
   helping, hunch, hunk, hurl, incurve, interest, knuckleball,
   large amount, lateral, lateral pass, loaf, lob, lot, lump, mass,
   measure, meed, mess, modicum, moiety, morsel, nugget, number,
   outcurve, pack, parcel, paring, parlay, part, particle, pass, pat,
   peg, percentage, piece, pitch, play, portion, proportion, put,
   quantity, quantum, quota, rake-off, rasher, ration, scoop, scrap,
   screwball, segment, serve, service, shard, share, shaving, shiver,
   shot, shot-put, shred, shy, sinker, slice, slider, sling, sliver,
   small amount, small share, smithereen, snack, snatch, snip,
   snippet, snowball, spitball, spitter, splinter, stake, stitch,
   stock, stockpile, stump, sum, tatter, throw, toss, upcurve, wad,
   wager