Wiktionary
n. A tool used to draw circles, usually consisting of two arms joined at one end in such a way that the arms can be opened and closed; one of the arms is pointed at its free end while the other holds a pencil, pencil lead or some other implement for making marks.
Usage examples of "pair of compasses".
In algebraic geometry a circle ended up being defined as `a conic section that passes through the two imaginary circular points at infinity', which sure puts a pair of compasses in their place.
The plate showed two long, tapering follicles joined together at their stems and then separating like a pair of compasses set at an acute angle.
If on Friday night you had taken a pair of compasses and drawn a circle with a radius of five miles round the Woking sand pits, I doubt if you would have had one human being outside it, unless it were some relation of Stent or of the three or four cyclists or London people lying dead on the common, whose emotions or habits were at all affected by the new-comers.
But the puzzle is to show how I was able to draw this spiral with so much exactitude without using anything but a pair of compasses and the sheet of paper on which the diagram was made.
By the light of the fire he cut two little flat rulers, which he joined together at one end so as to form a pair of compasses, whose legs could separate or come together.
Captain Servadac was evidently in no hurry to betake himself to rest, but seating himself at his table, with a pair of compasses and a sheet of tracing-paper, he began to draw, with red and blue crayons, a variety of colored lines, which could hardly be supposed to have much connection with a topographical survey.
Steve had hurried off a moment before and returned with a pair of compasses in his hand.