1. a blue liquid or powder added to laundry to make white fabrics appear whiter
2. the process of treating metal with heat to create a protective blue-black finish
Usage: technical

Examples

• She added a small amount of blueing to the wash water.
• The old-fashioned blueing made the white sheets look brighter.
• My grandmother always used blueing when doing laundry.
• The gunsmith applied blueing to protect the rifle barrel from rust.
• Blueing gives steel a distinctive dark finish.
• You can buy blueing at most hardware stores.