Term
idea
For Plato, an unchanging pattern of a thing that can be grasped only by thought: the equal itself, the beautiful itself, the just itself. The things we see only approach their ideas.
Phaedo, Plato
Explained in
- Phaedo, Plato
- A Treatise Concerning the Principles of Human Knowledge, George Berkeley
For Berkeley: any sensation or image in the mind, whether a colour, a sound, a smell or a picture in the imagination. This is his term, not the everyday meaning of the word.