CNF

A propositional formula is a CNF formula, meaning Conjunctive Normal Form, if it is a conjunction of disjunction of literals (a literal is a propositional variable or its negation). Hence, a CNF is a formula of the form: $K_1 \wedge K_2 \wedge \ldots \wedge K_n$ , where each $K_i$ is of the form $l_{i1} \vee l_{i2} \vee \ldots \vee l_{im}$ for literals $l_{ij}$ and some $m$ (which can vary for each $K_i$ ).

Example: $(x\vee y \vee \neg z) \wedge (y\vee \neg w \vee \neg u) \wedge (x\vee v)$ .