Mordant

Part of speech: noun (n.)

1. Any corroding substance used in etching.

2. Any substance, as alum or copperas, which, having a twofold attraction for organic fibers and coloring matter, serves as a bond of union, and thus gives fixity to, or bites in, the dyes.

3. Any sticky matter by which the gold leaf is made to adhere.

Part of speech: verb (v.)

To subject to the action of, or imbue with, a mordant; as, to mordant goods for dyeing.

Part of speech: adjective (a.)

1. Biting; caustic; sarcastic; keen; severe.

2. Serving to fix colors.