Sinus | Dictionary of Greek and Roman Geography

sinus
sĭnus, ūs, m. I In gen., a bent surface (raised or depressed), a curve , fold , a hollow , etc...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
sinus
sinus ūs, m a bent surface, curve, fold, hollow, coil: draco . . . conficiens sinūs e corpore flexo...

An Elementary Latin Dictionary
Sinus
·pl of Sinus. II. Sinus ·noun A cavity; a depression. III. Sinus ·noun A dilated vessel or canal. ...

Webster's Dictionary of the English Language