The Stacks project

Definition 12.23.1. Let $\mathcal{A}$ be an abelian category. A filtered differential object $(K, F, d)$ is a filtered object $(K, F)$ of $\mathcal{A}$ endowed with an endomorphism $d : (K, F) \to (K, F)$ whose square is zero: $d \circ d = 0$.