agent

In linguistics, a grammatical agent is the thematic relation of the cause or initiator to an event. The agent is a semantic concept distinct from the subject of a sentence as well as from the topic. While the subject is determined syntactically, primarily through word order, the agent is determined through its relationship to the action expressed by the verb. For example, in the sentence "The little girl was bitten by the dog", girl is the subject, but dog is the agent. The word agent comes from the present participle , ('the one doing') of the Latin verb , to 'do' or 'make'. Theory Typically, the situation is denoted by a sentence, the action by a verb in the sentence, and the agent by a noun phrase. For example, in the sentence "Jack kicked the ball", Jack is the agent and the ball is the patient. In certain languages, the agent is declined or otherwise marked to indicate its grammatical role. Modern English does not mark the agentive grammatical role of a noun in a sentence. Although certain nouns do have a permanent trait of agency (agent noun: runner, kicker, etc.), an agent noun is not necessarily an agent of a sentence: "Jack kicked the runner".