Dictionary.net

An instrument for describing circles, measuring figures, etc., consisting of two, or (rarely) more, pointed branches, or legs, usually joined at the top by a rivet on which they move.

An instrument, consisting of two movable legs, for describing circles, measureing figures, &c.

An instrument with two legs for describing circles, &c.

To stretch round; to inclose; to encircle or surround; to go or walk round; to grasp or embrace; to accomplish; to plot; to contrive.

n. pl. An instrument of two pointed legs, moving on a rivet, for describing circles, measuring figures, &c.