1 [C] a circular journey or track round sth 环行；绕一圈: The cars have to complete ten circuits of the track. 参赛汽车必须跑完十圈才行。

2 [C] a complete circular path that an electric current can flow around 电路 ☞picture at switch 见switch插图

3 [sing] a series of sports competitions, meetings or other organized events that are regularly visited by the same people 巡回（体育比赛、会议或其他有组织的活动）: She's one of the best players on the tennis circuit. 她是网球巡回赛的最佳选手之一。