From luke ("light"); white -- white.
1. light, bright, brilliant: τά ἱμάτια ... λευκά ὡς τό φῶς, Matthew 17:2; especially bright or brilliant from whiteness, (dazzling) white: spoken of the garments of angels, and of those exalted to the splendor of the heavenly state, Mark 16:5; Luke 9:29; Acts 1:10; Revelation 3:5; Revelation 4:4; Revelation 6:11; Revelation 7:9, 13; Revelation 19:14 (shining or white garments were worn on festive and state occasions, Ecclesiastes 9:8; cf. Heindorf on Horace sat. 2, 2, 61); with ὡσεί or ὡς ὁ χιών added: Mark 9:3 R L; Matthew 28:3 (ἵπποι λευκοτεροι χιόνος, Homer, Iliad 10, 437); ἐν λευκοῖς namely, ἱματίοις (added in Revelation 3:5; Revelation 4:4), John 20:12; Revelation 3:4; cf. Winers Grammar, 591 (550); (Buttmann, 82 (72)); used of white garments as the sign of innocence and purity of soul, Revelation 3:18; of the heavenly throne, Revelation 20:11.
2. (dead) white: Matthew 5:36 (opposed to μέλας); Revelation 1:14; Revelation 2:17; Revelation 4:4; Revelation 6:2; Revelation 14:14; Revelation 19:11; spoken of the whitening color of ripening grain, John 4:35.