Oxygen's electrons, e.g.

• Santa's reindeer team, e.g.
• Two quartets?
• Coxswain's crew, at most
• The Ivies, e.g.
• Two foursomes
• Ennead minus one
• Hexad plus duad
• Two vocal quartets

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Octad \Oc"tad\, n. [Gr. ?, ?, the number eight.] (Chem.) An atom or radical which has a valence of eight, or is octavalent. A group of eight things.

WordNet Word definitions in WordNet
n. the cardinal number that is the sum of seven and one [syn: eight , 8 , VIII , eighter , eighter from Decatur , ogdoad , octonary , octet ]