1. Any of several plants of the genus Dahlia native to the mountains of Mexico, Central America, and Colombia, having tuberous roots and showy, rayed, variously colored flower heads.
2. The flower head of one of these plants.

[New Latin Dahlia, genus name, after Anders Dahl (1751-1787), Swedish botanist.]

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.