1. One of five offspring born in a single birth.
2. A group or combination of five associated by common properties or behavior.

[From QUINTUPLE (modeled on TRIPLET).]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.