Dictionary.com
Thesaurus.com

pearl oyster

American  

noun

  1. any of several marine bivalve mollusks of the family Pteriidae, some of which form pearls of great value, inhabiting waters of eastern Asia and off the coasts of Panama and Baja California.

pearl oyster British  

noun

  1. any of various tropical marine bivalves of the genus Pinctada and related genera: a major source of pearls

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of pearl oyster

First recorded in 1685–95

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.