Look up bluing in Wiktionary, the free dictionary.
Bluing (steel) is a passivation process in which steel is partially protected against rust
Bluing may also refer to:
- Bluing (fabric), a blue dye used to improve the appearance of fabrics
- Bluing (hair), a blue dye used to improve the appearance of hair
- "bluing" of machine parts to check for tolerances, see engineer's blue