v. 25B6; verb
the sky was beginning to lighten : BECOME/GROW LIGHTER, brighten.
the first touch of dawn lightened the sky : MAKE LIGHTER, make brighter, brighten, light up, illuminate, throw/cast light on, shine on, irradiate; poetic/literary illumine.
he used lemon juice to lighten his hair : WHITEN, make whiter, bleach, blanch, make paler; fade, wash out, decolorize.
darken.