Experience is the process through which conscious organisms perceive the world around them. Experiences can be accompanied by active awareness on the part of the person having the experience, although they need not be. Experience is the primary subject of various subfields of philosophy, including the philosophy of perception, the philosophy of mind, and phenomenology.
Several different senses of the word "experience" should be distinguished from one another. In the sense of the word under discussion here, "experience" means something along the lines of "perception", "sensation", or "observation". In this sense of the word, knowledge gained from experience is called "empirical knowledge" or "a posteriori knowledge". This can include descriptive knowledge (e.g. finding out that certain things are true based on sensory experience), procedural knowledge (e.g. learning how to perform a particular task based on sensory experience), or knowledge by acquaintance (e.g. familiarity with certain people, places, or objects based on direct exposure to them).
In ordinary language, the word "experience" may instead sometimes refer to one's level of competence or expertise, either in general or confined to a particular subject. In this sense of the word, "experience" generally refers to know-how rather than descriptive knowledge (or in other words, on-the-job training rather than book-learning). This article is not about "experience" in this sense, but is instead about the immediate perception of events.