1. (n.) Cognizance by the senses or intellect; apprehension by the bodily organs, or by the mind, of what is presented to them; discernment; apprehension; cognition.

2. (n.) The faculty of perceiving; the faculty, or peculiar part, of man's constitution by which he has knowledge through the medium or instrumentality of the bodily organs; the act of apprehending material objects or qualities through the senses; -- distinguished from conception.

3. (n.) The quality, state, or capability, of being affected by something external; sensation; sensibility.

4. (n.) An idea; a notion.