1560s, from Middle French ritual or directly from Latin ritualis "relating to (religious) rites," from ritus "religious observance or ceremony, custom, usage," perhaps from PIE root *re- "to reason, count." Related: Ritually.
ritual (n.)
1640s, from ritual (adj.).
ritual killing
a ritual dance of Haiti
risotto
risque
Ritalin
ritardando
rite
ritual
ritualistic
Ritz
ritzy
rival
rivalrous