microdot

from WordNet (r) 3.0 (2006)

microdot
    n 1: photograph reduced to the size of a dot (usually for
         purposes of security)

from Moby Thesaurus II by Grady Ward, 1.0

23 Moby Thesaurus words for "microdot":
      bulletin board, card, catalog card, disc, file, filing card, film,
      index card, library catalog, magnetic tape, microcard, microfiche,
      microfilm, motion-picture film, phonograph record, platter,
      scoreboard, scorecard, scoresheet, slip, tape, ticker tape,
      videotape