Quartets times two

• Bytes, usually
• White and black pawns, e.g
• Day in Ascot rearranged for groups of eight
• Sets of eight
• Pieces of eight?
• Planets and notes in the musical scale
• Candles in a menorah, e.g.
• Series of eight
• Wild coast hiding first sign of danger for boat crews?

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