proportional compasses: drawing instrument consisting of two legs each with points at either end; used for transferring dimensions in enlarged or reduced ratio.
proportional dividers: drawing instrument consisting of two legs each with points at either end; used for transferring dimensions in enlarged or reduced ratio.
proportional instrument: unusual instrument used to mechanically perform functions in trigonometry.
protractor: instrument for setting out and measuring degrees.
quadragesima: the 40 days of Lent or the first Sunday in Lent.