Idioms and Phrases with in practice
Actually, in fact, especially as opposed to theoretically or in principle. For example, In practice this contraption seems to work, although no one knows how or why. [Second half of 1500s] Also see put into practice.
In the exercise of a particular profession, as in She's an obstetrician and has been in practice for at least ten years. [c. 1700]
In a state of being exercised so as to maintain one's skill, as in This trumpeter is always in practice. [Early 1600s] For an antonym, see out of practice.