Idealism is the philosophy that believes the ultimate nature of reality is ideal, or based upon ideas, values, or essences. The external, or real world cannot be separated from consciousness, perception, mind, intellect and reason in the sense of science. The word comes from the Greek word ἰδέα.
In some doctrines of idealistic thought the ideal relates to direct and immediate knowledge of subjective mental ideas, or images.
The English Wiktionary has a dictionary definition (meanings of a word) for: idealism