n. Anything that differentiates, or causes differentiation (in any sense)
the GNU version of the Collaborative International Dictionary of English
n. One who, or that which, differentiates.
The Century Dictionary and Cyclopedia
n. One who or that which differentiates: as, the radicals of written Chinese serve as differentiators of the sense, while the phonetics play the same part as regards sound.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a person who (or that which) differentiates
Word Usage
"Obviously the government plays a role, but I think the main differentiator here is: it is the homeowner who steps forward and who says, I need help."