round

a round of golf is 18 holes.

a round of poker is a set of games where each player around the table takes turns dealing.

a round of nightclubs means going to a series of nightclubs, and then back to the first one.

a round in boxing is 3 minutes.

a round in MMA is 5 minutes.

a circle is round.

a round-robin tournament is where each player/team plays each other team.
for example, in international hockey, a round-robin tournament means that Canada plays Finland, Sweden, the Czech Republic, Russia and the U.S. Then the teams with the most wins go on to the semi-finals.