Etymology: Middle English trewe, from Old English trēowe faithful; akin to Old High German gitriuwi faithful, Old Irish derb sure, and probably to Sanskrit dāruṇa hard, dāru wood — more at tree
Date: before 12th century
a. steadfast, loyal
b. honest, just
c. archaic truthful
(1) being in accordance with the actual state of affairs <true description> (2) conformable to an essential reality (3) fully realized or fulfilled <dreams come true> b. ideal, essential c. being that which is the case rather than what is manifest or assumed <the true dimension of the problem> d. consistent <true to character> 3. a. properly so called <true love> <the true faith> <the true stomach of ruminant mammals> b. (1) possessing the basic characters of and belonging to the same natural group as <a whale is a true but not a typical mammal> (2) typical <the true cats> 4. legitimate, rightful <our true and lawful king> 5. a. that is fitted or formed or that functions accurately b. conformable to a standard or pattern ; accurate 6. determined with reference to the earth's axis rather than the magnetic poles <true north> 7. logically necessary 8. narrow, strict <in the truest sense> 9. corrected for error • trueness noun II. adverb Date: 14th century 1. in accordance with fact or reality 2. a. without deviation <the bullet flew straight and true> b. without variation from type <breed true> III. noun Date: circa 1536 1. truth, reality — usually used with the 2. the quality or state of being accurate (as in alignment or adjustment) — used in the phrases in true and out of true IV. transitive verb (trued; trueing; also truing) Date: 1841 to make level, square, balanced, or concentric ; bring or restore to a desired mechanical accuracy or form <true up a board> <true up an engine cylinder>
New Collegiate Dictionary. 2001.