the larva of a predaceous diving beetle, of the genus Dytiscus.
Origin of water tiger
First recorded in 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for water tiger
There she found a fine lodge, and all things ready for her reception, and she became the wife of the water-tiger.
After she had plunged into the lake, she found herself in the hold of a water-tiger, who drew her to the bottom.