The Collaborative International Dictionary of English v.0.48:

Crunch \Crunch\, v. t.
   To crush with the teeth; to chew with a grinding noise; to
   craunch; as, to crunch a biscuit.
   [1913 Webster] Crunk

The Collaborative International Dictionary of English v.0.48:

Crunch \Crunch\ (kr[u^]nch), v. i. [imp. & p. p. Crunched
   (kr[u^]ncht); p. pr. & vb. n. Crunching.] [Prob. of
   imitative origin; or cf. D. schransen to eat heartily, or E.
   scrunch.]
   1. To chew with force and noise; to craunch.
      [1913 Webster]

            And their white tusks crunched o'er the whiter
            skull.                                --Byron.
      [1913 Webster]

   2. To grind or press with violence and noise.
      [1913 Webster]

            The ship crunched through the ice.    --Kane.
      [1913 Webster]

   3. To emit a grinding or craunching noise.
      [1913 Webster]

            The crunching and ratting of the loose stones. --H.
                                                  James.
      [1913 Webster]

WordNet (r) 3.0 (2006):

crunch
    n 1: the sound of something crunching; "he heard the crunch of
         footsteps on the gravel path"
    2: a critical situation that arises because of a shortage (as a
       shortage of time or money or resources); "an end-of-the year
       crunch"; "a financial crunch"
    3: the act of crushing [syn: crush, crunch, compaction]
    v 1: make a crushing noise; "his shoes were crunching on the
         gravel" [syn: crunch, scranch, scraunch, crackle]
    2: press or grind with a crushing noise [syn: crunch,
       cranch, craunch, grind]
    3: chew noisily; "The children crunched the celery sticks" [syn:
       crunch, munch]
    4: reduce to small pieces or particles by pounding or abrading;
       "grind the spices in a mortar"; "mash the garlic" [syn:
       grind, mash, crunch, bray, comminute]

Moby Thesaurus II by Grady Ward, 1.0:

186 Moby Thesaurus words for "crunch":
   appulse, atomize, bang, bang into, belch, bind, bite, blare, blat,
   bray, break into pieces, break to pieces, break up, brunt,
   bulldozing, bulling, bump, bump into, burr, buzz, cackle, cannon,
   carambole, carom, carom into, caw, champ, chaw, chew, chirr, chomp,
   chump, clang, clangor, clank, clash, climacteric, clutch, collide,
   collision, come into collision, complication, concuss, concussion,
   confront each other, convergence of events, crack up, crack-up,
   crash, crash into, craunch, crisis, critical juncture,
   critical moment, critical point, croak, crossroads, crucial period,
   crump, crush, crux, cut to pieces, dash into, demolish, diffuse,
   disperse, disrupt, embarrassing position, embarrassment, emergency,
   encounter, exigency, extremity, fall foul of, fine how-do-you-do,
   fission, foul, fragment, grate, grind, groan, growl, grumble,
   hammering, hell to pay, high pressure, hinge, hit, hit against,
   hobble, hot water, how-do-you-do, hurt, hurtle, imbroglio, impact,
   imperativeness, impinge, impingement, jam, jangle, jar, juncture,
   knock, knock against, make mincemeat of, masticate, mauling, meet,
   meeting, mess, mince, mix, moment of truth, morass, munch,
   onslaught, parlous straits, pass, percuss, percussion, pickle,
   pinch, plight, predicament, press, pressure, pretty pass,
   pretty pickle, pretty predicament, pulverize, push, quagmire,
   quicksand, ramming, rasp, repercussion, rub, ruminate, run into,
   scatter, scranch, scrape, scratch, scrunch, shatter, shiver, shock,
   showdown, sideswipe, slam into, sledgehammering, slough,
   smack into, smash, smash into, smash up, smash-up, smashing, snarl,
   snore, splinter, spot, squash, squeeze, squish, stew,
   sticky wicket, strait, straits, stress, strike, strike against,
   swamp, tension, thrusting, tight spot, tight squeeze, tightrope,
   tricky spot, turn, turning point, twang, unholy mess, urgency,
   whomp



The Jargon File (version 4.4.7, 29 Dec 2003):

crunch


    1. vi. To process, usually in a time-consuming or complicated way. Connotes
    an essentially trivial operation that is nonetheless painful to perform.
    The pain may be due to the triviality's being embedded in a loop from 1 to
    1,000,000,000. ?FORTRAN programs do mostly number-crunching.?

    2. vt. To reduce the size of a file by a complicated scheme that produces
    bit configurations completely unrelated to the original data, such as by a
    Huffman code. (The file ends up looking something like a paper document
    would if somebody crunched the paper into a wad.) Since such compression
    usually takes more computations than simpler methods such as run-length
    encoding, the term is doubly appropriate. (This meaning is usually used in
    the construction file crunch(ing) to distinguish it from number-crunching
    .) See compress.

    3. n. The character #. Used at XEROX and CMU, among other places. See 
    ASCII.

    4. vt. To squeeze program source into a minimum-size representation that
    will still compile or execute. The term came into being specifically for a
    famous program on the BBC micro that crunched BASIC source in order to make
    it run more quickly (it was a wholly interpretive BASIC, so the number of
    characters mattered). Obfuscated C Contest entries are often crunched;
    see the first example under that entry.


The Free On-line Dictionary of Computing (30 December 2018):

crunch

   1.  To process, usually in a time-consuming or
   complicated way.  Connotes an essentially trivial operation
   that is nonetheless painful to perform.  The pain may be due
   to the triviality's being embedded in a loop from 1 to
   1,000,000,000.  "Fortran programs do mostly number
   crunching."

   2.  To reduce the size of a file without losing
   information by a scheme such as Huffman coding.  Since such
   lossless compression usually takes more computations than
   simpler methods such as run-length encoding, the term is
   doubly appropriate.

   3. The hash character.  Used at XEROX and CMU, among
   other places.

   4. To squeeze program source to the minimum size that will
   still compile or execute.  The term came from a BBC
   Microcomputer program that crunched BBC BASIC source in
   order to make it run more quickly (apart from storing
   keywords as byte codes, the language was wholly interpreted,
   so the number of characters mattered).  Obfuscated C Contest
   entries are often crunched; see the first example under that
   entry.

   [Jargon File]

   (2007-11-12)