Mordant \Mor"dant\, a. [F., p. pr. of mordere to bite; L. mordere. See Morsel.]

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

2. (Dyeing & Calico Printing) Serving to fix colors.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Mordant \Mor"dant\, n. [F., originally, biting.]

1. Any corroding substance used in etching.

2. (Dyeing & Calico Printing) 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. (Gilding) Any sticky matter by which the gold leaf is made to adhere.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Mordant \Mor"dant\, v. t. [imp. & p. p. Mordanted; p. pr. & vb. n. Mordanting.]

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

Source: Webster's Revised Unabridged Dictionary (1913)