Wood
Old English wudu, from a Germanic word related to Welsh gwŷdd ‘trees’.
wiktionary
From Middle English wode, from Old English wudu, widu(“wood, forest, grove; tree; timber”), from Proto-West Germanic *widu, from Proto-Germanic *widuz(“wood”), from Proto-Indo-European *h₁weydʰh₁-(“to separate”).
Cognate with Dutch wede(“wood, twig”), Middle High German wite(“wood”), Danish ved(“wood”), Swedish ved(“firewood”), Icelandic viður(“wood”). Unrelated to Dutch woud(“forest”), German Wald(“forest”) (see English wold).
From Middle English wood, from Old English wōd(“mad, insane”). See the full etymology at wode.
Back-formation from peckerwood.
etymonline
wood (n.)
Old English wudu, earlier widu "tree, trees collectively, forest, grove; the substance of which trees are made," from Proto-Germanic *widu- (source also of Old Norse viðr, Danish and Swedish ved "tree, wood," Old High German witu "wood"), from PIE *widhu- "tree, wood" (source also of Welsh gwydd "trees," Gaelic fiodh- "wood, timber," Old Irish fid "tree, wood"). Out of the woods "safe" is from 1792.
wood (adj.)
"violently insane" (now obsolete), from Old English wod "mad, frenzied," from Proto-Germanic *woda- (source also of Gothic woþs "possessed, mad," Old High German wuot "mad, madness," German wut "rage, fury"), from PIE *wet- (1) "to blow; inspire, spiritually arouse;" source of Latin vates "seer, poet," Old Irish faith "poet;" "with a common element of mental excitement" [Buck]. Compare Old English woþ "sound, melody, song," Old Norse oðr "poetry," and the god-name Odin.
