A more thorough explanation:

In certain professions, a small business is referred to as a practice instead of a business, store, or shop. This term is commonly used by those who run their own legal or medical business, such as a law practice or a chiropractic practice. The term "practice" is usually used for smaller businesses, while larger ones are called firms.

Practice can also refer to the expected behaviors, activities, or procedures among a group of people. This can be called common practice or best practice. For example, in the medical field, it is common practice to wash your hands before and after seeing a patient to prevent the spread of germs. In the legal field, it is best practice to keep client information confidential.

These practices can be important in legal cases when determining if someone acted reasonably given a certain situation or if they conformed to industry standards. For instance, if a doctor followed the common practice of washing their hands before seeing a patient, they would be less likely to be considered negligent if the patient still got sick.