The Collaborative International Dictionary of English v.0.48:

Honk \Honk\ (h[o^][ng]k), n. [Of imitative origin.] (Zool.)
   The cry of a wild goose. -- Honk"ing, n.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Honk \Honk\ (h[o^][ng]k), n.
   1. To make a sound like the honk of a goose.
      [PJC]

   2. Specifically: To sound the horn on an automobile or other
      motor vehicle.
      [PJC]

WordNet (r) 3.0 (2006):

honk
    n 1: the cry of a goose (or any sound resembling this)
    v 1: make a loud noise; "The horns of the taxis blared" [syn:
         honk, blare, beep, claxon, toot]
    2: use the horn of a car [syn: honk, claxon]
    3: cry like a goose; "The geese were honking" [syn: honk,
       cronk]
    4: eject the contents of the stomach through the mouth; "After
       drinking too much, the students vomited"; "He purged
       continuously"; "The patient regurgitated the food we gave him
       last night" [syn: vomit, vomit up, purge, cast,
       sick, cat, be sick, disgorge, regorge, retch,
       puke, barf, spew, spue, chuck, upchuck, honk,
       regurgitate, throw up] [ant: keep down]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "honk":
   bay, beep, bell, blare, blast, blat, blow, blow the horn, bray,
   bugle, cackle, call, carol, caw, chatter, cheep, chirk, chirp,
   chirr, chirrup, chitter, chuck, clack, clarion, cluck,
   cock-a-doodle-doo, coo, croak, cronk, crow, cuckoo, drum, fanfare,
   flourish of trumpets, gabble, gaggle, gobble, guggle, hoo, hoot,
   peal, peep, pip, pipe, quack, roll, scold, shriek, sing, sound,
   sound a tattoo, sound taps, squawk, squeal, tantara, tantarara,
   taps, tarantara, tattoo, toot, tootle, trill, trumpet,
   trumpet blast, trumpet call, tweedle, tweet, twit, twitter, warble,
   whistle, wind