Definition of resilium in US English:

resilium

noun

Zoology
  • In a bivalve mollusc: the resilient central part of the shell hinge, which tends to force apart the two valves and is composed chiefly of fibrous conchiolin.

Origin

Late 19th century; earliest use found in William Healey Dall (1845–1927), natural historian, paleontologist, and malacologist. From either resili- or classical Latin resilīre to jump back, recoil + -um, after Latin nouns ending in -um.

Pronunciation

resilium

/rɪˈzɪlɪəm/