a large, dark brown, commercial sponge, Spongia graminea, of Florida, the West Indies, and the Gulf of Mexico.
Origin of grass sponge
An Americanism dating back to 1870–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for grass sponge
This is one of the species of sponges of the third commercial grade, which bear the trade-name of "grass-sponge."The Sea-beach at Ebb-tide|Augusta Foote Arnold