'Fixative' definitions:

Definition of 'fixative'

From: WordNet
noun
A compound (such as ethanol or formaldehyde) that fixes tissues and cells for microscopic study
noun
A varnish dissolved in alcohol and sprayed over pictures to prevent smudging

Definition of 'Fixative'

From: GCIDE
  • Fixative \Fix"a*tive\, n. That which serves to set or fix colors or drawings, as a mordant. [1913 Webster]