Mactra
/ˈmaktrə/Zoology
noun
A genus of marine bivalve molluscs of the family Tridacnidae (formerly Mactridae), which are typically several centimetres long with thin, triangular to ovate shells; (also mactra, plural mactrae, mactras) a mollusc of this genus, or its shell.
Origin
Late 18th century; earliest use found in Thomas Pennant (1726–1798), naturalist, traveller, and writer. From scientific Latin Mactra (Linnaeus Systema Naturae (ed. 12, 1767) I. ii. 1125) from ancient Greek μάκτρα kneading trough, cognate with μάσσειν to knead.