Quiz: Remember the definition of mal de mer?
c.1400, from Latin manualis "of or belonging to the hand; that can be thrown by hand," from manus "hand, strength, power over; armed force; handwriting," from PIE *man- (2) "hand" (cf. Old Norse mund "hand," Old English mund "hand, protection, guardian," German Vormund "guardian," Greek mane "hand").
early 15c., "service book used by a priest," from Old French manuel "handbook" (also "plow-handle"), from Late Latin manuale "case or cover of a book, handbook," noun use of neuter of Latin manualis (see manual (adj.)). Meaning "a concise handbook" of any sort is from 1530s.