noun

An institution of learning: This could be a school, college, or university where people go to learn and study.
A society of scholars, scientists, or artists: This kind of academy promotes and advances knowledge, research, or professional practice in a specific field.
A place of training: This could be for specific skills or professions, such as a military academy or a police academy.

Example

1. The young artist enrolled in a prestigious art academy to hone her skills.
2. After graduating from the police academy, he began his career as a patrol officer.
3. The renowned scientist was elected to the National Academy of Sciences for his groundbreaking research.