1. A flock of geese.
2. A cluster or group: "A gaggle of photographers huddled on the sidewalk beside a swelling crowd of onlookers" (Gioia Diliberto).
[Middle English gagel, from gagelen, to cackle, probably of imitative origin.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.