fixative

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Something that fixes, protects, or preserves, especially:
2. n. A liquid preservative applied to artwork, such as watercolor paintings or charcoal drawings.
3. n. A solution used to preserve and harden fresh tissue for microscopic examination.
4. n. A liquid mixed with perfume to prevent rapid evaporation.

Century Dictionary and Cyclopedia

1. Serving to fix, or make fixed or stable: as, a fixative substance or process.
2. n. Anything which serves to render fixed or stable, as a mordant with reference to colors; specifically, a weak solution of shellac in alcohol applied to charcoal and crayon drawings with an atomizer to fix them and prevent them from being rubbed.
3. n. In perfumery, a substance used to detain from too speedy evaporation a highly volatile ingredient of agreeable odor. The substance so used may itself be inodorous or may contribute to the blended odor of the mixed perfume.
4. n. Same as amboceptor.

Wiktionary

1. n. A substance that fixes, protects, or preserves.
2. adj. Serving to fix or bind.

GNU Webster's 1913

1. n. That which serves to set or fix colors or drawings, as a mordant.

WordNet 3.0

1. n. a compound (such as ethanol or formaldehyde) that fixes tissues and cells for microscopic study
2. n. a varnish dissolved in alcohol and sprayed over pictures to prevent smudging