rate constant

symbol: $k$
https://doi.org/10.1351/goldbook.08203
Term generally used for the rate coefficient of a reaction that is believed to be an elementary reaction.
Notes:
  1. In contrast to a rate coefficient, a rate constant should be independent of concentrations, but in general both rate constant and rate coefficient vary with temperature.
  2. Rate constant and rate coefficient are often used as synonymous.
Source:
PAC, 2022, 94, 353. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)) on page 493 [Terms] [Paper]