Faithful, as to a friend, vow, or cause; loyal. See Synonyms at faithful.
Sincerely felt or expressed; unfeigned: true grief.
Fundamental; essential: his true motive.
Rightful; legitimate: the true heir.
Exactly conforming to a rule, standard, or pattern: trying to sing true B.
Accurately shaped or fitted: a true wheel.
Accurately placed, delivered, or thrown.
Quick and exact in sensing and responding.
Determined with reference to the earth's axis, not the magnetic poles: true north.
Conforming to the definitive criteria of a natural group; typical: The horseshoe crab is not a true crab.
Narrowly particularized; highly specific: spoke of probity in the truest sense of the word.
Computer Science Indicating one of two possible values taken by a variable in Boolean logic or a binary device.
adv.
In accord with reality, fact, or truthfulness.
Unswervingly; exactly: The archer aimed true.
So as to conform to a type, standard, or pattern.
tr.v.
trued, tru·ing or true·ing, trues To position (something) so as to make it balanced, level, or square: trued up the long planks. n.
Truth or reality. Used with the.
Proper alignment or adjustment: out of true.
[Middle English trewe, from Old English trēowe, firm, trustworthy; see deru- in Indo-European roots.] true'ness n.
Word History: The words true and tree are joined at the root, etymologically speaking. In Old English, the words looked and sounded much more alike than they do now: "tree" was trēow and "true" was trēowe. The first of these comes from the Germanic noun *trewam; the second, from the adjective *treuwaz. Both these Germanic words ultimately go back to an Indo-European root *deru- or *dreu-, appearing in derivatives referring to wood and, by extension, firmness. Truth may be thought of as something firm; so too can certain bonds between people, like trust, another derivative of the same root. A slightly different form of the root, *dru-, appears in the word druid, a type of ancient Celtic priest; his name is etymologically *dru-wid-, or "strong seer."
[troo] 
adjective, tru⋅er, tru⋅est, noun, adverb, verb, trued, tru⋅ing or true⋅ing.