mouthpiece

UK: ˈmaʊθpiːs | US: ˈmaʊθpiːs

Definition
  1. n. a part of a device or instrument that is placed in or near the mouth (e.g., of a musical instrument or breathing apparatus)

  2. n. a person or publication that expresses the opinions of an organization or group

  3. n. (slang) a lawyer, especially a defense attorney

Structure
mouth <oral opening>piece <part>
Etymology

The word "mouthpiece" originated in the late 16th century, combining "mouth" (Old English mūþ, meaning the oral cavity) and "piece" (Old French piece, meaning a part or segment). Initially, it referred literally to a part of an object placed in the mouth (e.g., a musical instrument). By the 18th century, it gained a figurative sense, describing a spokesperson or medium for communication, likening the person or publication to a conduit for speech, much like a literal mouthpiece channels sound.

Examples
  1. The trumpet’s mouthpiece was polished to a shine.

  2. The newspaper acted as a mouthpiece for the political party.

  3. His lawyer, a sharp mouthpiece, secured his acquittal.

  4. She cleaned the snorkel’s mouthpiece before diving.

  5. The union’s mouthpiece criticized the new labor policies.