The Collaborative International Dictionary of English v.0.48:

Roach \Roach\, n. (Zool.)
   A cockroach.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Roach \Roach\, n. [OE. rroche; cf. AS. reohha, D. rog, roch, G.
   roche, LG. ruche, Dan. rokke ray, Sw. rocka, and E. ray a
   fish.]
   1. (Zool.)
      (a) A European fresh-water fish of the Carp family
          (Leuciscus rutilus). It is silver-white, with a
          greenish back.
      (b) An American chub (Semotilus bullaris); the fallfish.
      (c) The redfin, or shiner.
          [1913 Webster]

   2. (Naut.) A convex curve or arch cut in the edge of a sail
      to prevent chafing, or to secure a better fit.
      [1913 Webster]

   As sound as a roach [roach perhaps being a corruption of a
      F. roche a rock], perfectly sound.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Roach \Roach\, v. t.
   1. To cause to arch.
      [1913 Webster]

   2. To cut off, as a horse's mane, so that the part left shall
      stand upright.
      [1913 Webster]

WordNet (r) 3.0 (2006):

roach
    n 1: a roll of hair brushed back from the forehead
    2: the butt of a marijuana cigarette
    3: street names for flunitrazepan [syn: R-2, Mexican valium,
       rophy, rope, roofy, roach, forget me drug,
       circle]
    4: any of numerous chiefly nocturnal insects; some are domestic
       pests [syn: cockroach, roach]
    5: European freshwater food fish having a greenish back [syn:
       roach, Rutilus rutilus]
    v 1: comb (hair) into a roach
    2: cut the mane off (a horse)

The Free On-line Dictionary of Computing (19 January 2023):

roach

    A Bell Labs term meaning destroy, especially of a
   data structure.  Hardware gets toasted or fried, software
   gets roached.

   [Why?]

   [Jargon File]

   (1999-02-08)


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

roach
 vt.

    [Bell Labs] To destroy, esp. of a data structure. Hardware gets toasted
    or fried, software gets roached. Probably derived from '70s and '80s drug
    slang; marijuana smokers used ‘roach’ to refer to the unsmokable remnant of
    a joint, and to ‘roach’ a joint was therefore to destroy it.