Il Foreign Language testing, the section of a test in which lexicon, morphology and grammar are explicitly assessed, different from other abilities such as "oral comprehension" or "written production".

Definitions you can find around there are mostly generic, not specific, and leave "space" for a lot of testing modalities. The Spanish translation, "competencia lingüística", is even more confusing, since nobody seems to have worked out a precise guide to refer to in order to say that a given kind of item belongs or not to "language in use".