a nonfading blue dye or pigment.
a person who is true-blue.
(in the 17th century) the color adopted by the Covenanters in contradistinction to the royal red.
true-bluePronunciation: (trOO'blOO'), [key]
unwaveringly loyal or faithful; staunch; unchangingly true.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.