the.com/osmolality

means A measure of how many dissolved particles are packed into a kilogram of fluid, which determines which way water flows across a membrane.

from Built from 'osmo-', drawn from Greek 'osmos' meaning 'push' or 'thrust' (the same root as 'osmosis'), fused with '-ality' to make it an abstract, measurable noun. The term entered chemistry and physiology as scientists needed precise language for concentration measured per kilogram of solvent — a cousin, but not a twin, of 'osmolarity', which measures the same push per liter of solution instead.