által

által is a Hungarian postposition used to mark the agent or means by which an action is performed. It follows the noun phrase that represents the agent or instrument and introduces the role of that actor in the event described by the verb. In function, it roughly corresponds to the English by or through in passive constructions, and to by means of or via when indicating method or instrument.

The typical pattern is X által Y, where X denotes the agent or instrument and Y denotes the action or result. This usage is especially common in formal or written Hungarian, notably in passive sentences and in descriptions of actions carried out by people or organizations. The agent may be a person, a group, an institution, or any entity capable of acting.

Examples illustrate the usage:

- A könyvet a tanár által írták meg. (The book was written by the teacher.)

- A döntést a közgyűlés által hozták meg. (The decision was made by the assembly.)

In addition to expressing agency, által can also convey means or method in certain contexts, particularly with verbs of creation, publication, or decision-making, where the actor or instrument performs the action through that agent.

Notes: által is a fixed postposition; it does not itself change form. The noun phrase before it inflects as required by Hungarian syntax, while the postposition remains invariant. In everyday speech, the agent phrase may sometimes be omitted if the agent is understood from context, but vagyáltal remains a standard option in more formal or explicit sentences.