The word 'wood' descends from Old English 'wudu' or 'widu' (tree, trees collectively, forest, grove, timber), from Proto-Germanic *widuz (wood, forest, tree), from PIE *widʰu- (tree, wood). The semantic history reveals an important shift: in Old English, 'wudu' primarily meant a forest or a collection of trees growing together, and only secondarily the material obtained from them. We named the substance after the place, not the place after the substance.
The PIE root *widʰu- is well attested. Old Norse 'viðr' (tree, wood, forest), Old High German 'witu' (wood), Old Saxon 'widu,' and Irish 'fiodh' (wood, tree — via Celtic *widus) all descend from the same proto-form. The Sanskrit 'vídhu' has been tentatively compared, though this connection is not universally accepted.
The 'forest' sense of 'wood' survives powerfully in English place names. Sherwood Forest is 'shire-wood' — the forest belonging to the shire (county). Hollywood is 'holly-wood' — a grove of holly trees. Wychwood is the forest of the Hwicce, an Anglo-Saxon tribe. Brentwood is 'burnt wood' — a forest that had been cleared by fire. Wedgwood (the pottery family) takes its name from 'wecg-wudu' — 'wedge-wood,' a forest where wood was split into wedges
The phrase 'the woods' (as in 'a walk in the woods' or 'we're not out of the woods yet') preserves the original sense intact. When English speakers say 'woods' to mean a forest, they are using the word exactly as Anglo-Saxon speakers used 'wudu' over a thousand years ago.
The material sense — wood as timber, as cut lumber, as a building and crafting substance — gradually became dominant as forests were cleared and the processed material became more culturally salient than the living ecosystem. By Middle English, 'wood' could readily mean either the forest or its product, and in Modern English, the material sense is primary for most speakers.
The adjective 'wooden' means both 'made of wood' and, metaphorically, 'stiff, expressionless, lacking natural grace' — a wooden performance, a wooden smile. This metaphorical sense captures something real about wood as a material: it is rigid, it does not flex or flow, it holds its shape stubbornly. 'Deadwood' means useless material or people — wood that is no longer alive, no longer productive. 'Knock on wood' (or 'touch wood' in British English) is a superstitious gesture of uncertain origin, possibly connected to pre-Christian beliefs about protective spirits
The distinction between 'wood' (the material) and 'woods' (a forest) is one of those quiet English patterns that native speakers navigate instinctively but that reveals deep history upon inspection: the singular tends toward the material, the plural toward the place. 'A piece of wood' versus 'a walk in the woods' — substance versus landscape, product versus source.