Viscosity
Etymology
From Latin viscum, "mistletoe" and the sticky birdlime made from its berries; the adjective viscosus meant "sticky, gluey." The image is of something clinging and slow to move. Physics turned it into a precise measure of the internal friction that resists flow within a fluid.
noun · /vis-KOSS-ih-tee/
A fluid’s internal resistance to flowing — the reason honey pours slowly and water pours fast.
What it names
The felt "thickness" of a process — how much friction and drag any system puts between wanting to do something and it actually moving.
Example
The company’s approval process had the viscosity of cold syrup — every good idea slowed to a crawl before reaching anyone who could say yes.
Related idea
Viscosity is smooth, orderly resistance within a flow; turbulence is the opposite regime, where the flow breaks into chaotic, swirling motion.