The Collaborative International Dictionary of English v.0.48:

Lash \Lash\ (l[a^]sh), n. [OE. lasche; cf. D. lasch piece set
   in, joint, seam, G. lashe latchet, a bit of leather, gusset,
   stripe, laschen to furnish with flaps, to lash or slap, Icel.
   laski gusset, flap, laska to break.]
   1. The thong or braided cord of a whip, with which the blow
      is given.
      [1913 Webster]

            I observed that your whip wanted a lash to it.
                                                  --Addison.
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   2. A leash in which an animal is caught or held; hence, a
      snare. [Obs.]
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   3. A stroke with a whip, or anything pliant and tough; as,
      the culprit received thirty-nine lashes.
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   4. A stroke of satire or sarcasm; an expression or retort
      that cuts or gives pain; a cut.
      [1913 Webster]

            The moral is a lash at the vanity of arrogating that
            to ourselves which succeeds well.     --L'Estrange.
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   5. A hair growing from the edge of the eyelid; an eyelash.
      [1913 Webster]

   6. In carpet weaving, a group of strings for lifting
      simultaneously certain yarns, to form the figure.
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The Collaborative International Dictionary of English v.0.48:

Lash \Lash\, v. i.
   To ply the whip; to strike; to utter censure or sarcastic
   language.
   [1913 Webster]

         To laugh at follies, or to lash at vice. --Dryden.
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   To lash out, to strike out wildly or furiously; also used
      figuratively.
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The Collaborative International Dictionary of English v.0.48:

Lash \Lash\, v. t. [Cf. D. lasschen to fasten together, lasch
   piece, joint, Sw. laska to stitch, Dan. laske stitch. See
   Lash, n. ]
   To bind with a rope, cord, thong, or chain, so as to fasten;
   as, to lash something to a spar; to lash a pack on a horse's
   back.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lash \Lash\ (l[a^]sh), v. t. [imp. & p. p. Lashed; p. pr. &
   vb. n. Lashng.]
   1. To strike with a lash; to whip or scourge with a lash, or
      with something like one.
      [1913 Webster]

            We lash the pupil, and defraud the ward. --Dryden.
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   2. To strike forcibly and quickly, as with a lash; to beat,
      or beat upon, with a motion like that of a lash; as, a
      whale lashes the sea with his tail.
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            And big waves lash the frighted shores. --Dryden.
      [1913 Webster]

   3. To throw out with a jerk or quickly.
      [1913 Webster]

            He falls, and lashing up his heels, his rider
            throws.                               --Dryden.
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   4. To scold; to berate; to satirize; to censure with
      severity; as, to lash vice.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lash
    n 1: any of the short curved hairs that grow from the edges of
         the eyelids [syn: eyelash, lash, cilium]
    2: leather strip that forms the flexible part of a whip [syn:
       lash, thong]
    3: a quick blow delivered with a whip or whiplike object; "the
       whip raised a red welt" [syn: whip, lash, whiplash]
    v 1: beat severely with a whip or rod; "The teacher often
         flogged the students"; "The children were severely
         trounced" [syn: flog, welt, whip, lather, lash,
         slash, strap, trounce]
    2: lash or flick about sharply; "The lion lashed its tail"
    3: strike as if by whipping; "The curtain whipped her face"
       [syn: whip, lash]
    4: bind with a rope, chain, or cord; "lash the horse" [ant:
       unlash]

Moby Thesaurus II by Grady Ward, 1.0:

189 Moby Thesaurus words for "lash":
   anchor, assail, attack, band, bandage, baste, bastinado, bawl out,
   beat, belabor, belt, bend, berate, bind, bind up, birch,
   blacksnake, blister, blow, boil, bolt, box, brace, bridle, buffet,
   bullwhack, bullwhip, bundle, cage, cane, cast anchor, castigate,
   cat, chain, charge, chase, chew out, cilia, cinch, club,
   come to anchor, corral, cowhide, criticize, crop, cudgel, cuff,
   cut, dash, disembark, do up, dock, drench, drive, drop the hook,
   drove, drub, enchain, entrammel, excoriate, fasten, fetter, fix,
   flagellate, flagellum, flail, flap, flay, fling, flog, fustigate,
   gad, gadfly, gird, girdle, girt, girth, give a whipping,
   give the stick, goad, gyve, hamper, handcuff, herd, hide, hobble,
   hog-tie, hopple, horsewhip, jaw, kedge, kedge off, knout, kurbash,
   lace, lambaste, lash and tie, lather, lay anchor, lay on, leash,
   make fast, manacle, moor, needle, nudge, oxgoad, peg down, picket,
   pin down, pinion, pistol-whip, poke, pommel, prick, prod, pummel,
   punch cattle, punish, put in irons, quirt, race, rawhide,
   razor strap, restrain, ride herd on, roast, rope, round up, rowel,
   scarify, scathe, scold, scorch, scourge, secure, shackle, shepherd,
   shoot, sjambok, skin alive, slap, slash, smack, smite, spank,
   splice, spur, sting, straitjacket, strap, strike, stripe, stroke,
   swaddle, swathe, swinge, switch, tear, teem, tether, thong, thrash,
   thump, thwack, tie, tie down, tie up, tongue-lash, trammel,
   trounce, truncheon, truss, upbraid, vituperate, wag, waggle,
   wallop, wave, wear out, whack, whale, whip, whiplash, whop, wire,
   wrangle, wrap, wrap up