Definition of protegulum in US English:
protegulum
noun
Zoology
In brachiopods: the initial or embryonic form of the shell, or of each valve of the shell.
Origin
Late 19th century. From pro- + classical Latin tēgulum roofing from tegere to cover + -ulum.
Pronunciation
protegulum
/prə(ʊ)ˈtɛɡjʊləm/