Sets of eight

• Bytes, usually
• Wild coast hiding first sign of danger for boat crews?
• Planets and notes in the musical scale
• Candles in a menorah, e.g.
• Groups of eights
• Flag football teams
• Quarterfinal groups, e.g.
• Quartets times two
• Pairs of quartets

Wiktionary Word definitions in Wiktionary
n. (plural of octad English)