from Wiktionary, Creative Commons Attribution/Share-Alike License
n. A citrus tree, a cross between a lime and a kumquat
n. The fruit from this tree
Blend of lime and kumquat (Wiktionary)
I'm still trying to figure out the precise connection to Dr. Walter T. Swingle, early 20th century USDA botanist...and creator of such citrus hybrids like the "citrange," "citrangequat," and "limequat."