transitive verb.
To modify, especially to increase, the rate of (a chemical reaction) by catalysis.
transitive verb.
To bring about; initiate.
transitive verb.
To produce fundamental change in; transform.
The Century Dictionary and Cyclopedia
In physical chemistry, to act upon by catalysis: said of a substance which accelerates a chemical reaction while it is itself left unchanged at the end of the reaction.
the GNU version of the Collaborative International Dictionary of English
transitive verb.
to cause (a chemical reaction) to proceed more quickly by contacting the reactant(s) with another substance.