a detailed description of how a chemical reaction occurs
a detailed description of the way a reaction occurs and is based on the known experimental data about the reaction
a detailed (theoretical) description of how we think the chemical reaction proceeds
a series of elementary reactions or elementary steps that lead from reactants to products
a set of steps at the molecular level
a step by step description of the separate steps that occur during a chemical reaction
a stepwise description of the reaction path
mechanism. A list of all elementary reactions that occur in the course of an overall chemical reaction.
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs.