octad

[ ok-tad ]
/ ˈɒk tæd /

noun

a group or series of eight.
Chemistry. an element, atom, or group having a valence of eight.

Origin of octad

1835–45; < Greek oktad- (stem of oktás) group of eight, equivalent to okt- oct- + -ad -ad1

OTHER WORDS FROM octad

oc·tad·ic, adjective

British Dictionary definitions for octad

octad
/ (ˈɒktæd) /

noun

a group or series of eight
chem an element or group with a valency of eight

Derived forms of octad

octadic, adjective

Word Origin for octad

C19: from Greek oktās, from oktō eight