mid-13c., from Old French perle (13c.) and directly from Medieval Latin perla (mid-13c.), of unknown origin. Perhaps from Vulgar Latin *pernula, diminutive of Latin perna, which in Sicily meant "pearl," earlier "sea-mussel," literally "ham, haunch, gammon," so called for the shape of the mollusk shells.
Other theories connect it with the root of pear, also somehow based on shape, or Latin pilula "globule," with dissimilation. The usual Latin word for "pearl" was margarita (see margarite).
For pearls before swine, see swine. Pearl Harbor translates Hawaiian Wai Momi, literally "pearl waters," so named for the pearl oysters found there; transferred sense of "effective sudden attack" is attested from 1942 (in reference to Dec. 7, 1941).
epithelial pearl n.
See keratin pearl.
A small sphere of thin glass containing amyl nitrite or other volatile fluid, designed to be crushed, as in a handkerchief, so that its contents can be inhaled.
Any of a number of small tough masses of mucus occurring in the sputum in asthma.
A smooth, slightly iridescent, white or grayish rounded growth inside the shells of some mollusks. Pearls form as a reaction to the presence of a foreign particle, and consist of thin layers of mother-of-pearl that are deposited around the particle. The pearls of oysters are often valued as gems.