auxochrome

Century Dictionary and Cyclopedia

1. n. In chem., noting those groups contained in dyes which enable them to combine with the fiber of the cloth or with a mordant. The most important of these are the hydroxyl-, amino-, sulpho-, and carboxyl-groups.

Wiktionary

1. n. obsolete ,(chemistry) any atom or group which, when added to a chromophore, causes a bathochromic shift in its spectrum