Process. (1) The way of working. (2) The course of procedure.
Produce. In astronomy the word produce means the lengthening of a line. It is a mathematical term.
Protractor. [See Fig. 98].
Quarter circle. [See Appendix B].
Ray. (1) A single line of light or heat. (2) The path of light and heat.
Relative position. The position of a thing when compared with the position of something else. See Position.
Revolution. The turning of a thing completely round on its axis.
Revolve. (1) To turn completely round a circle. (2) To turn on an axis, as a top, or the Earth.
Rigid. Firm, that which cannot be easily moved out of its place.
Ring. [See Appendix B].