round

round in music, a perpetual canon on a tune that returns to its beginning in which all the voices enter at the unison or the octave. An example is Sumer Is Icumen In . Rounds were popular in 17th-century England when the catch reached its height. The catch was originally just a simple round, e.g., Three Blind Mice, written in a single line with the effect gained by having another singer come in ( "make the catch" ) at the right time. Later, comic effects, often quite bawdy, were added, using the interweaving of the parts. The Rounds, Catches and Canons of England (1864) by E. F. Rimbault is a comprehensive collection. The term round was also used to designate a dance performed in a circle and, by extension, to the tunes for such dances.

round. Anything circular, or almost circular, such as a round (i.e. semicircular) arch, round-arched style (Rundbogenstil), round (as opposed to prismatic) billet, round church (i.e. circular on plan), round moulding (e.g. torus), round pediment (i.e. segmental or semicircular), round ridge (i.e. with a half-cylindrical crest or ridge-tile), round tower (as in Irish round towers with conical caps and certain other bell-towers in England and Italy), and round window (as in a Catherine-wheel or rose-window).

round n. the amount of ammunition needed to fire one shot.
v. pass and go around (something) so as to move on in a changed direction: the ship rounded the cape at dawn.