baseball club; baseball team
Refers to an organized baseball club, typically at a school, university, or company. Can also mean the team itself.
兄は高校の野球部に入っています。
My older brother is in the high school baseball club.
うちの会社の野球部は毎週土曜日に練習し
My younger brother joined the baseball club in junior high.
Our company's baseball team practices every Saturday.
He belonged to the baseball club back in high school.
Baseball club practice continues until evening every day.
I got injured and ended up quitting the baseball club.
野球部 is a school or company baseball club, whereas 球団 refers only to a professional franchise, so learners can easily mix up the two.
Compound of 野球 (baseball) and 部 (club, department).