>> > Dice? Do you mean "dies"
maybe?
The OED (Volume IV: Creel - Duzepere) lists BOTH as plural for "die".
Is THAT authoritative enough?
(y'all made me walk across the room)
But, the closest to THIS meaning of "die" that it offers is a mold, or a
cubic random number generator.
Unlikely that a plinth is what we mean.