ǵʰey-
“winter, cold, snow”winter, snow
Root for winter, yielding Latin hiems (winter), Greek kheima (storm), Sanskrit hima-.
Discussion
The PIE root *ǵʰey- (winter, cold, snow) produced the word for the coldest season across the major branches, confirming that the PIE speakers lived in a climate with distinct winters — a detail consistent with the steppe homeland hypothesis.
Latin hiems (winter — genitive hiemis) continues the root and generated: hibernal (pertaining to winter), hibernate (to spend the winter in dormancy — from hibernāre, a practice the Romans observed in certain animals), and the rarely used hiemal. The name Hibernia (Ireland — possibly "the wintry land," though this etymology is debated) may preserve the root in a toponym.
Greek kheimṓn (χειμών, "winter, storm, tempest") preserves the root with the expected Greek treatment of the palato-velar. The word carried a double sense: winter as a season and storm as a meteorological event — the connection being that winter IS the storm season. The derivative khímaira (chimera — originally a she-goat born in winter, then the fire-breathing monster of myth) shows an unexpected extension.
Sanskrit himá- (cold, winter, snow) and the related Himālaya (himá + ālaya, "abode of snow" — the name of the mountain range that defines South Asia's northern boundary) provide the Indo-Iranian reflex. The Himalayas are, etymologically, the "winter-dwelling" — the place where snow lives.
Old English does not continue this specific root for winter — English winter (OE winter) derives from a different formation, possibly from PIE *wed- (wet) or *wind- (white). But the Latinate hibernation and the geographic Himalayas reintroduce the root into English through learned channels.
Old Irish gam (winter) and Lithuanian žiemà (winter) confirm the Celtic and Baltic reflexes. Old Church Slavonic zima (winter) continues the Slavic form — Russian zimá (winter) is the direct descendant.
The root's survival across virtually every branch with the same meaning confirms winter as a PIE cultural reality: these were people who experienced, endured, and named the cold season.
Notes
Pokorny 425-426. English Himalayas (abode of snow), hibernate.