contratype
Contratype is a term used in linguistics and philosophy of language to refer to a sentence or expression that has the opposite meaning or truth value of another. For example, "All dogs bark" and "No dogs bark" are contranyms, as they cannot both be true, nor can they both be false simultaneously. This relationship is often contrasted with contradiction, where two statements are directly opposed in meaning and one must be true and the other false.
The concept of contratype is important in understanding logical relationships between propositions and in analyzing how