defined
v.v. to explain the exact meaning of a word or idea. You can also use it to describe the shape or edges of something very clearly.
v. to state the precise meaning of a term or concept; alternatively, to delineate the outline or boundaries of an object with clarity. Transitive, requiring a direct object.
The dictionary defined the word clearly.
The contract defined the responsibilities of each partner to avoid future legal disputes.
While the architect defined the structural parameters of the building, the interior designer was responsible for the aesthetic choices that gave the space its character.
The verb is transitive and takes a direct object. In its passive form ('is defined by'), it often identifies a characteristic that makes something what it is.
He defined about the problemHe defined the problemDefine is a transitive verb and does not take the preposition 'about' before its object.