From Wiktionary

practice (plural practices)

1. Repetition of an activity to improve skill.

   He will need lots of practice with those lines before he performs them.

2. The ongoing pursuit of a craft or profession, particularly in medicine or the fine arts.

   She ran a thriving medical practice.

3. The observance of religious duties which a Church requires of its members.
4. A customary action, habit, or behavior; a manner or routine.

   It is the usual practice of employees there to wear neckties only when meeting with customers.

   It is good practice to check each door and window before leaving.

5. Actual operation or experiment, in contrast to theory.

   That may work in theory, but will it work in practice?