Old English holt "woods, forest, grove, thicket," common in place names, from Proto-Germanic *hultam- (source also of Old Frisian, Old Norse, Middle Dutch holt, Dutch hout, German Holz "a wood, wood as timber"), from PIE *kldo- (source also of Old Church Slavonic klada "beam, timber;" Russian koloda, Lithuanian kalada "block of wood, log;" Greek klados "twig;" Old Irish caill "wood"), from root *kel- "to strike, cut."

"fungal decay in timber," by 1779, from dry (adj.) + rot (n.). Figurative sense of "concealed or unsuspected inward degeneration" is by 1821.

1520s, originally of timber, from verbal phrase rough hew "to hew coarsely without smoothing" (1520s); see rough (adj.) + hew (v.).

1809, "one employed in rafting timber," agent noun from raft (v.). By 1978 as "one who uses a recreational raft."

"mill (originally driven by water or wind) for sawing timber into boards and planks," 1550s; see saw (n.1) + mill (n.1).

word-forming element meaning "tree," from Greek dendron "tree," sometimes especially "fruit tree" (as opposed to hylē "timber"), from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," also forming words for "wood, tree."