oct

eight

Spelled oct · octo 'eight'

Greek oktō and Latin octo mean eight: an octopus has eight feet, an octagon eight angles, and an octet eight performers.

Words built from it

octopus — a sea creature with eight arms
oct (eight) + pus (foot)
octagon — a shape with eight sides
oct (eight) + gon (angle)
octagonal — having eight sides
oct (eight) + gon (angle) + -al
octet — a group of eight, especially musicians
oct (eight) + -et (small group)
octave — a span of eight musical notes
oct (eight) → Latin octavus (eighth)
octogenarian — a person in their eighties
Latin octo (eight) → octogeni (eighty each) → octogenarius (of eighty) → octogenarian

nocturnal — from Latin nox/noct- 'night' — the 'oct' here is part of 'noct', unrelated to octo 'eight'