- octonary⇄adj. 1. having to do with the number eight; consisting of eight.
2. proceeding by eighths; having eight as its base.
Ex. an octonary system of counting. - octonary⇄noun 1. a group of eight; ogdoad.
2. an octave or octet. - octonary⇄octonary, adjective, noun, pl.-naries.