Entailment

In pragmatics (linguistics), entailment is the relationship between two sentences where the truth of one requires the truth of the other. For example, the sentence The president was assassinated. entails The president is dead..

Entailment differs from implication, where the truth of one suggests the truth of the other, but does not require it. For example, the sentence Mary had a baby and got married implicates that she had a baby before the wedding, but this is cancellable by adding -- not necessarily in that order. Entailments are not cancellable.

Entailment also differs from presupposition in that in presupposition, the truth of what one is presupposing is taken for granted.