The Collaborative International Dictionary of English v.0.48:

Rep \Rep\ (r[e^]p), n. [Prob. a corruption of rib: cf. F. reps.]
   A fabric made of silk or wool, or of silk and wool, and
   having a transversely corded or ribbed surface.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rep \Rep\ (r[e^]p), a.
   Formed with a surface closely corded, or ribbed transversely;
   -- applied to textile fabrics of silk or wool; as, rep silk.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rep
    n 1: informal abbreviation of `representative'
    2: a fabric with prominent rounded crosswise ribs [syn: rep,
       repp]

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

REP

    A directive used in IBM object code card
   decks (and later PTF Tapes) to REPlace fragments of already
   assembled or compiled object code prior to link edit.
   Recompiling or reassembling the source code to produce a
   whole new object module was only possible if the source code
   was available, which it rarely was (if you had the object you
   were lucky!)  It was also quicker to apply incremental changes
   with REP cards and they also circumvented the checksums and
   card sequence numbers present in the object code.

   (1998-07-16)