A term sometimes used for a rate coefficient. For example, if the rate equation is: \[v=k\ \text{[A]}\ \text{[B]}\] the function k[A] is the pseudo first-order rate constant (or first-order rate coefficient) with respect to B. Similarly, k[B] is the pseudo first-order rate constant (or first-order rate coefficient) with respect to A. The term pseudo rate constant is particularly useful when the concentration of one reactant is much greater than that of another.