dice

Dice comes from Middle English dys, the plural form of dy — see the word die for the singular. The spelling and pronunciation with a hard 's' sound settled in over time.

Because people came to feel dys as a collective term rather than a true plural, the voiceless /s/ sound stuck around instead of softening, and the spelling dice followed that pronunciation — similar to how pence works as the collective form of penny.

Dice is simply the plural of die, so the two words share the same root; pence is mentioned as a comparable case of a plural that hardened into its own collective form.