true

Concise Oxford English Dictionary © 2008 Oxford University Press:
true/truː/

▶adjective (truer, truest)

• 1 in accordance with fact or reality.

  ■ rightly or strictly so called; genuine: true love.

  ■ real or actual.

• 2 accurate or exact.

  ■ (true to) accurately conforming to (a standard or expectation).

  ■ (of a note) exactly in tune.

  ■ (of a compass bearing) measured relative to true north.

  ■ correctly positioned or aligned; upright or level.

• 3 loyal or faithful.

  ■ chiefly archaic honest: all good men and true.

▶verb (trues, truing or trueing, trued) bring into the exact shape or position required.

– phrases
come true actually happen or become the case.
out of (the) true not in the correct or exact shape or alignment.
true to form (or type) being or behaving as expected.

– derivatives
trueness noun.

– origin OE trēowe, trȳwe ‘steadfast, loyal’; rel. to truce.