The Collaborative International Dictionary of English v.0.48:

Beef \Beef\ (b[=e]f), n. [OE. boef, befe, beef, OF. boef, buef,
   F. b[oe]ef, fr. L. bos, bovis, ox; akin to Gr. boy^s, Skr.
   g[=o] cow, and E. cow. See 2d Cow.]
   1. An animal of the genus Bos, especially the common
      species, Bos taurus, including the bull, cow, and ox, in
      their full grown state; esp., an ox or cow fattened for
      food.

   Note: [In this, which is the original sense, the word has a
         plural, beeves (b[=e]vz).]
         [1913 Webster]

               A herd of beeves, fair oxen and fair kine.
                                                  --Milton.
         [1913 Webster]

   2. The flesh of an ox, or cow, or of any adult bovine animal,
      when slaughtered for food.

   Note: [In this sense, the word has no plural.] "Great meals
         of beef." --Shak.
         [1913 Webster]

   3. Applied colloquially to human flesh.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Beef \Beef\ (b[=e]f), a.
   Of, pertaining to, or resembling, beef.
   [1913 Webster]

   Beef tea, essence of beef, or strong beef broth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

beef
    n 1: cattle that are reared for their meat [syn: beef, beef
         cattle]
    2: meat from an adult domestic bovine [syn: beef, boeuf]
    3: informal terms for objecting; "I have a gripe about the
       service here" [syn: gripe, kick, beef, bitch,
       squawk]
    v 1: complain; "What was he hollering about?" [syn: gripe,
         bitch, grouse, crab, beef, squawk, bellyache,
         holler]

Moby Thesaurus II by Grady Ward, 1.0:

268 Moby Thesaurus words for "beef":
   Brahman, Indian buffalo, air a grievance, altercation, amperage,
   arm, armipotence, aurochs, authority, avoirdupois, beef cattle,
   beef extract, beef tea, beefiness, beefing, beeves, bellyache,
   bellyaching, bickering, bison, bitch, bitching, black power, bleat,
   blow off, boggle, bossy, bouillon, bovine, bovine animal, boycott,
   brawl, brawn, brawniness, brute force, buffalo, bull, bullock,
   bully, bully beef, calf, call in question, carabao, cattle,
   challenge, charge, charisma, charqui, chipped beef, clamor, clout,
   cogence, cogency, complain, complaining, complaint, compulsion,
   compunction, cow, crab, critter, croak, cry out against,
   dairy cattle, dairy cow, deadweight, demonstrate,
   demonstrate against, demonstration, demur, demurrer,
   destructive criticism, dint, dispute, dissent, dogie, dried beef,
   drive, duress, effect, effectiveness, effectuality, elasticity,
   energy, enter a protest, exception, expostulate, expostulation,
   falling-out, fatness, faultfinding, flower power, force,
   force majeure, forcefulness, fret, fret and fume, full blast,
   full force, fuss, gravity, grievance, grievance committee, gripe,
   griping, groan, groaning, gross weight, grouch, ground beef,
   grouse, grousing, growl, grumble, grumbling, grunt, hamburger,
   heaviness, heft, heftiness, heifer, holler, hornless cow, howl,
   huskiness, indignation meeting, influence, involuntary muscle,
   jerky, kick, kicking, kine, leppy, liveweight, lodge a complaint,
   main force, main strength, mana, march, maverick, might,
   might and main, mightiness, milch cow, milcher, milk cow, milker,
   moxie, muley cow, muley head, murmur, murmuring, muscle,
   muscle power, muscularity, musculature, musk-ox, mutter, neat,
   neat weight, net, net weight, nonviolent protest, object,
   objection, overbalance, overweight, ox, oxen, pastrami, peeve,
   peevishness, pet peeve, petulance, physique, picket, picketing,
   pizzazz, ponderability, ponderosity, ponderousness, poop, potence,
   potency, potentiality, poundage, power, power pack,
   power structure, power struggle, powerfulness, prepotency,
   press objections, productiveness, productivity, protest,
   protest demonstration, protestation, puissance, pull, punch, push,
   qualm, querulousness, raise a howl, rally, register a complaint,
   remonstrance, remonstrate, remonstration, rhubarb, roast beef,
   salt beef, scolding, scruple, sinew, sinewiness, sinews, sit in,
   sit-in, sniping, squabble, squawk, squawking, state a grievance,
   steam, steer, stirk, stot, strength, strike, strong arm, suet,
   superiority, superpower, take on, teach in, teach-in, thew,
   thewiness, thews, tiff, tone, tonnage, underweight, validity,
   vehemence, vigor, vim, virility, virtue, virulence, vitality,
   voluntary muscle, wattage, weight, weightiness, whining, wisent,
   yak, yammer, yap, yapping, yawp, yearling, yell bloody murder,
   yelp, zebu