Definition 15.74.1. Let $R$ be a ring. Denote $D(R)$ the derived category of the abelian category of $R$-modules.
An object $K$ of $D(R)$ is perfect if it is quasi-isomorphic to a bounded complex of finite projective $R$-modules.
An $R$-module $M$ is perfect if $M$ is a perfect object in $D(R)$.