1. Having the component parts closely compacted together; crowded or compact: a dense forest; dense population.
2. Having relatively high density; as with, being rowded closely together; compact: a dense population.
3. Hard to penetrate; thick: a dense jungle.
4. Permitting little light to pass through, because of compactness of matter: dense glass; a dense fog.
5. Opaque, with good contrast between light and dark areas.
6. Difficult to understand because of complexity or obscurity.
7. Slow to apprehend; "thickheaded".
8. A slang term for "stupid; slow-witted; dull".
9. Intense; extreme.
10. Relatively opaque; transmitting little light; such as, a photographic negative, optical glass, or color.
11. Difficult to understand or follow because of being closely packed with ideas or complexities of style: "He wrote a dense philosophical essay."