The Collaborative International Dictionary of English v.0.48:

Modicum \Mod"i*cum\, n. [L., fr. modicus moderate, fr. modus.
   See Mode.]
   A little; a small quantity; a measured supply. "Modicums of
   wit." --Shak.
   [1913 Webster]

         Her usual modicum of beer and punch.     --Thackeray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

modicum
    n 1: a small or moderate or token amount; "England still expects
         a modicum of eccentricity in its artists"- Ian Jack

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "modicum":
   ace, allotment, allowance, atom, big end, bigger half, bit, bite,
   budget, butt, chip, chunk, clip, clipping, collop, commission,
   contingent, crumb, cut, cutting, dab, dash, deal, destiny,
   dividend, dole, dollop, dot, dram, dribble, driblet, drop, dwarf,
   end, equal share, farthing, fate, fleck, flyspeck, fragment, gob,
   gobbet, grain, granule, groat, hair, half, halver, handful,
   helping, hint, hunk, interest, iota, jot, little, little bit, lot,
   lota, lump, measure, meed, mess, minim, minimum, minutiae, mite,
   moiety, molecule, morsel, mote, nutshell, ounce, paring, part,
   particle, pebble, percentage, piece, pinch, pittance, point,
   portion, proportion, quantum, quota, rake-off, rasher, ration,
   scintilla, scoop, scrap, scruple, segment, shard, share, shaving,
   shiver, shred, slice, sliver, small share, smidgen, smidgin,
   smitch, smithereen, snack, snatch, snip, snippet, spark, speck,
   splinter, spoonful, spot, stake, stitch, stock, stump, suggestion,
   tatter, thimbleful, tinge, tiny bit, tittle, touch, trifle,
   trifling amount, trivia, whit