nouninstrumental

The term "noun instrumental" refers to a grammatical case used in some languages to indicate the instrument, means, or agent by which an action is performed. This case typically answers the question "by what" or "with what" an action is carried out. While not present in English, it is common in many Indo-European languages, including Russian, Polish, Latin, and Sanskrit.

In Russian, for example, the instrumental case is marked by specific endings on nouns, pronouns, and adjectives. It often describes tools, methods, or means of action. For instance, the word "ножом" (nожом, "knife" in instrumental case) in the phrase "резать ножом" (rezatʹ nожom, "to cut with a knife") indicates the tool used for cutting. Similarly, in Polish, the instrumental case is used to express the means or instrument of an action, such as "nożem" (knife) in "ciął nożem" (he cut with a knife).

The instrumental case can also denote the agent in passive constructions or express a general idea of how something is done. For example, in Latin, the phrase "gladio caedit" ("he cuts with a sword") uses the instrumental case "gladio" to indicate the weapon used. In some languages, the instrumental case may also convey a sense of accompaniment or association, such as in Sanskrit, where it can describe the means or instrument of an action or the agent performing it.

The absence of an instrumental case in English is often compensated for by prepositional phrases, such as "with a knife" or "by means of." Languages that employ the instrumental case typically use it to provide clarity and precision in expressing the relationship between an action and its means or agent.