rival [L16th] A rival was originally someone with whom you had to share your water supply. Recorded in English from the late 16th century, the word goes back to Latin rivalis, which originally meant ‘person living on the opposite bank and using the same stream as another’. It comes via Latin rivus ‘stream’ from ripus *river. Derive [LME] was originally ‘draw a fluid through or into a channel’ and comes from de- ‘down, away’ and rivus.