density

Where does the word "density" come from? It comes from Latin densitas, and was adopted directly into English (1600s).

Density’s story begins in Latin: densitas meant “thickness, compactness.” Thickness, compactness, from densus (thick, dense). It reached English by 1600s as density. Settled as the physics word for mass per unit volume. Today, density means the mass of a substance per unit of volume.

1. Stage 1 · Latin · ancient densitas "thickness, compactness", thickness, compactness, from densus (thick, dense).
2. Stage 2 · English · 1600s density "the mass of a substance per unit volume", settled as the physics word for mass per unit volume.