solidus
sol.i.dus \'sa:l-*d-*s\ \-*-.di-, -.de-\ n or sol.i.di [ME, fr. LL, fr. L, solid] [ML, shilling, fr. LL; fr. its use as a symbol for shillings] pl 1: an ancient Roman gold coin introduced by Constantine and used to the fal l of the Byzantine Empire 2: DIAGONAL