[cal.i.ber] or cal.i.bre n [MF calibre, fr. OIt calibro, fr. Ar qalib shoemaker's last] (1567) 1 a: degree of mental capacity or moral quality b: degree of excellence or importance
2. a: the diameter of a bullet or other projectile b: the diameter of a bore of a gun usu. expressed in hundredths or thousandths of an inch and typically written as a decimal fraction ".32 ~"
3: the diameter of a round body; esp: the internal diameter of a hollow cylinder