having the component parts closely compacted together; crowded or compact

a dense forest; dense population.

stupid; slow-witted; dull.

intense; extreme

dense ignorance.

relatively opaque; transmitting little light, as a photographic negative, optical glass, or color.

difficult to understand or follow because of being closely packed with ideas or complexities of style

a dense philosophical essay.

Mathematics . of or pertaining to a subset of a topological space in which every neighborhood of every point in the space contains at least one point of the subset.