frustulum

[fruhs-tuh-luh m, -chuh-]
noun, plural frus·tu·la [fruhs-tuh-luh, -chuh-] /ˈfrʌs tə lə, -tʃə-/. Roman Catholic Church.
  1. a small breakfast permitted on fast days.

Origin of frustulum

From Latin, dating back to 1690–1700; see origin at frustule
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018