instrumental (adj./n.) (inst, INST)

In languages which express GRAMMATICAL relationships by means of INFLECTIONS, this term refers to the FORM taken by a NOUN PHRASE (often a single noun or PRONOUN), when it expresses such a notion as ‘by means of’ (as in Russian). The term has a special status in CASE grammar, where it refers to the SEMANTIC case of the INANIMATE entity causally involved in a verb’s action (e.g. the key in the key opened the door or the door was opened with a key), and is contrasted with AGENTIVE, DATIVE, etc. The instrumental case (‘the instrumental’) is also used in some predicative constructions in Russian, such as with the future and past of ‘to be’, e.g. On budet studentom ‘He will be a student’.