An interlocutor is someone you're having a conversation with. If you're discussing your favorite book with a friend, that friend is your interlocutor. If you're debating whether recess should be longer with your principal, the principal is your interlocutor.

Interlocutor is more formal than just saying “the person I'm talking to,” and you'll often see it in writing about debates, negotiations, or formal discussions. A diplomat meeting with a foreign leader would call that leader her interlocutor. A journalist interviewing someone might refer to that person as their interlocutor.

The word suggests genuine two-way communication, not just one person talking at another. Your interlocutor responds, asks questions, and contributes ideas. In a classroom discussion about a novel, each student becomes an interlocutor as they share their interpretations and respond to others' thoughts. The word reminds us that good conversations require both speaking and listening, and that the person across from you matters as much to the exchange as you do.