oc·to·nar·y 
(ŏktə-nĕr′ē)
(ŏktə-nĕr′ē)adj.
1. Of or relating to the number eight.
2. Consisting of eight members or of groups containing eight.
n. pl. oc·to·nar·ies
A group or set of eight.
[Latin octōnārius, containing eight, from octōnī, eight each, from octō, eight; see oktō(u) in the Appendix of Indo-European roots.]