The planets, e.g.

• A couple of quarters?
• Quarterfinals group, perhaps
• Phases of the moon, say
• Pie slices, often
• Group of eight
• Oxygen atom's protons, e.g.
• Bits in a byte, e.g

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 ]

Wiktionary Word definitions in Wiktionary
n. A group of eight things