1. 1. Any of various terrestrial turtles, especially one of the family Testudinidae, characteristically having thick clublike hind limbs and a high, rounded carapace.
   2. Chiefly British. A terrestrial or freshwater chelonian.
2. One that moves slowly; a laggard.

[Alteration (influenced by PORPOISE) of Middle English tortuce, from Medieval Latin tortūca, alteration of Late Latin tartarūcha, feminine of tartarūchus, of the underworld. See turtle¹.]

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.