'Truth' is PIE *deru- (firm as oak) — kin to 'tree,' 'trust,' 'truce,' and 'Druid' (oak-knower).
The quality or state of being in accordance with fact or reality; that which is true or in accordance with what is real.
From Old English 'trēowþ' (truth, faithfulness, fidelity, loyalty), from 'trēowe' (true, faithful, trustworthy), from Proto-Germanic *trewwaz (faithful, trustworthy), from PIE *deru- (firm, solid, steadfast — originally referring to the firmness of wood, especially oak). Truth is etymologically 'firmness' or 'faithfulness' — and the same PIE root that means 'firm as wood' gave us 'tree,' 'trust,' 'truce,' 'true,' and 'Druid' (oak-knower). Key roots: *deru- (Proto-Indo-European: "firm, solid, steadfast; tree