The word "balls" can refer to several things depending on the context. Most commonly, it refers to spherical objects used in sports and games, such as a soccer ball or basketball. It can also be used informally to refer to courage or audacity, as in the phrase "he has a lot of balls." Additionally, "balls" can refer to male reproductive organs in a colloquial sense.
The word "ball" comes from the Old Norse word "bǫll," which means a round object. The word has evolved through Middle English and has various meanings in different contexts related to spherical objects or games.