Learning is acquiring new, or modifying existing, knowledge, behaviors, skills, values, or preferences and may involve synthesizing different types of information.
(retrieved from http://en.wikipedia.org/wiki/Learning , 2013-01-21)
Learning can refer to cognitive skills (like remembering, calculating, etc.), psychomotorical abilities (swimm, walk, press a button, etc.) or affective or emotional responses (prefer, like, hate, etc.) (see Benjamin Bloom's Taxonomy of Learning Domains ). The process of learning can happen by purposeful actions aimed at aquiring skills like reading a book or attending classes, or happen unintentionally, for example by observation or by trial and error.