adjective denser dens′er, densest dens′·est

1. having the parts crowded together; packed tightly together; compact
2. difficult to get through, penetrate, etc. a dense fog, dense ignorance
3. slow to understand; stupid
4. Photog. opaque due to a heavy concentration of metallic silver: said of an overexposed or overdeveloped negative

Etymology: ME < L densus, compact < IE base *dens-, thick > Gr dasys, thick (used of hair), Hittite dassuš, strong