In older work in Western linguistics, especially in the grammar of Indo-European languages, the term oblique case refers to all cases other than the nominative and the vocative (these are also called direct cases).
This use of the term goes back to antiquity (Latin obliquus, itself based on a semantic loan from Greek).
- Chomsky, N. 1981. Lectures on Government and Binding, Foris, Dordrecht.
German obliquer Kasus