An Etymological Dictionary of Astronomy and Astrophysics

Having relatively high → density.
Math.: The quality of a subset A of a topological space X, indicating that
any point in X can be well approximated by points in A.

Etymology (EN): From L. densus “thick, crowded,” cognate with Gk. dasys “hairy, bushy, thick grown.”

Etymology (PE): Cagâl “dense, thick,” related to ceqer “stiff, hard, tough, firm” (dialectal Kermâni ceqel, Šândizi caqal),
caqâlé “stiff, unripe fruit.”