snew-
“to flow, swim, drip”Source of Latin natāre, Greek nein, English natant
Root for flowing or swimming, yielding Latin natāre (to swim) and Greek nein.
Discussion
The Proto-Indo-European root *snew- meant "to flow, to swim, to drip" and produced descendants relating to both liquid flow and its frozen counterpart. The root captures the movement of water in its various states, and its semantic range extends from swimming through nourishment (flowing sustenance) to snow (frozen water that flows from the sky).
In Germanic, the root produced Old English snāw, the direct ancestor of modern English snow. The initial *sn- cluster was preserved unchanged, making this one of the more transparent correspondences between Proto-Indo-European and modern English. German Schnee, Dutch sneeuw, and Swedish snö are close cognates. The connection between "flowing" and "snow" lies in the image of precipitation falling and drifting — snow as water that flows from the clouds.
Latin has no direct reflex of this particular root for "snow" (Latin nix "snow" comes from a different root, *snigʷʰ-), but the related concept of flowing nourishment appears in nutrire "to nourish, to feed" — from the zero-grade *snu-tri-, literally "to cause to flow" (as milk flows to nourish). This gave English nourish, nurse, nurture, nutrient, and nutrition. The semantic link between flowing and nourishing is ancient and widespread, reflecting the fundamental importance of liquid sustenance — milk, water, broth — in sustaining life.
Greek has nein "to swim" and nama "a flowing stream", both connected to this root complex. Sanskrit snáuti "drips, flows" preserves the original form closely.
The semantic triangle of *snew- — flowing water, falling snow, and nourishing sustenance — reveals a conceptual unity that modern speakers might not immediately recognise. The Proto-Indo-European speakers saw these as aspects of a single phenomenon: the movement of life-giving liquid, whether falling from the sky, running in streams, or flowing as milk from a mother's breast.