In grammar, the instructive case is a grammatical case used in the Finnish, Estonian, and Turkish languages. Wikipedia

grammatical case Wikidata

Noun case used to indicate means. It answers the question "how?", and in English, this is usually expressed by the prepositional phrase by means of, as in "by means of the house". Languages that use the instructive case include Finnish and (rarely) Estonian. Wiktionary

Case used to indicate means. Wiktionary (translation)