activation

Also contains definition of: degree of activation
https://doi.org/10.1351/goldbook.A00093
This word is used in different senses:
  1. Input of external energy into a chemical system is said to bring about activation of the system.
  2. An added substance that increases the rate of a catalysed reaction is known as an activator, and the effect is called activation. The degree of activation ╔Ťa is defined by: \[\varepsilon_{\text{a}}=\frac{v\,-\,v_{0}}{v_{0}} = \frac{v}{v_{0}} - 1\] where v 0 is the rate of the catalysed reaction in the absence of the activator and v is the rate of the catalysed reaction in the presence of the activator.
  3. When some of the energy required for a reaction to occur is provided by a previous exothermic chemical reaction there is said to be chemical activation.
See: catalysis, chemical activation
See also: activator, inhibition
Source:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 151 (https://doi.org/10.1351/pac199668010149)