This is the 7215th most frequent Chinese word.
網球
Tennis.
In this sentence, 網球 refers to the sport of tennis that the subject participates in.
我每天早晨都會打網球。
I play tennis every morning.
Here, 網球 represents an activity involving playing tennis, usually with equipment such as a racket and ball.
那孩子正在公園裡玩網球。
That child is playing tennis in the park.
In this instance, 網球 means tennis balls themselves, representing the actual equipment used in the sport.