the GNU version of the Collaborative International Dictionary of English
n. An agent that sensitizes.
The Century Dictionary and Cyclopedia
n. One who or that which sensitizes; specifically, in photography, the chemical agent or bath by which films or substances are rendered sensitive to light.
n. Same as amboceptor.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. (chemistry) a substance other than a catalyst that facilitates the start of a catalytic reaction