noun
or blue·ing ˈblüiŋ
( -s )
Etymology: from gerund of blue (III)
1. : the act of making blue
the bluing of steel
2. : something that gives a bluish tint: as
a. : a rinse for gray or white hair
b. : a preparation of blue or violet dyes used in laundering to counteract the yellowish tinge of white linen or cotton
3. : blue rot