Wordnet 3.0
NOUN (1)
1. 
 a flock of geese; 
VERB (1)
1. 
 make a noise characteristic of a goose; 
- Example: "Cackling geese"
The Collaborative International Dictionary of English v.0.48:
Gaggle \Gag"gle\ (g[a^]g"g'l), v. i. [imp. & p. p. Gaggled; p.
   pr. & vb. n. Gaggling.] [Of imitative origin; cf. D.
   gaggelen, gagelen, G. gackeln, gackern, MHG. g[=a]gen, E.
   giggle, cackle.]
   To make a noise like a goose; to cackle. --Bacon.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Gaggle \Gag"gle\, n. [Cf. Gaggle v. i.]
   1. (Zool.) A flock of wild geese, especially when on the
      ground. [Prov. Eng.] --Halliwell.
      [1913 Webster]
   2. Hence: A gathering of people, especially a noisy one.
      [PJC]
   3. Hence: Any clustered group of related objects.
      [PJC]
WordNet (r) 3.0 (2006):
gaggle
    n 1: a flock of geese
    v 1: make a noise characteristic of a goose; "Cackling geese"
Moby Thesaurus II by Grady Ward, 1.0:
54 Moby Thesaurus words for "gaggle":
   bevy, cackle, call, carol, caw, charm, chatter, cheep, chirk,
   chirp, chirr, chirrup, chitter, chuck, clack, cloud, cluck,
   cock-a-doodle-doo, coo, covey, croak, cronk, crow, cuckoo, drum,
   flight, flock, gabble, gobble, guggle, hive, honk, hoo, hoot,
   murmuration, peep, pip, pipe, plague, quack, roll, scold, sing,
   skein, spring, squawk, swarm, trill, tweet, twit, twitter, warble,
   watch, whistle