Experience is the knowledge or mastery of an event or subject gained through involvement in or exposure to it.
Compare various contemporary definitions given in the OED (2nd edition, 1989): "[...] 3. The actual observation of facts or events, considered as a source of knowledge.[...] 4. a. The fact of being consciously the subject of a state or condition, or of being consciously affected by an event. [...] b. In religious use: A state of mind or feeling forming part of the inner religious life; the mental history (of a person) with regard to religious emotion. [...] 6. What has been experienced; the events that have taken place within the knowledge of an individual, a community, mankind at large, either during a particular period or generally. [...] 7. a. Knowledge resulting from actual observation or from what one has undergone. [...] 8. The state of having been occupied in any department of study or practice, in affairs generally, or in the intercourse of life; the extent to which, or the length of time during which, one has been so occupied; the aptitudes, skill, judgement, etc. thereby acquired."
] Terms in philosophy such as "empirical knowledge" or "a posteriori knowledge" are used to refer to knowledge based on experience. A person with considerable experience in a specific field can gain a reputation as an expert. The concept of experience generally refers to know-how or procedural knowledge, rather than propositional knowledge: on-the-job training rather than book-learning.