There are numerous synonyms for the phrase "mouth part." Some common alternatives include "oral cavity," "oral apparatus," "oral region," and "buccal cavity." The term "oral cavity" is typically used to refer to the entire space inside the mouth, whereas "oral apparatus" is often used to describe the structures that make up the mouth, including the lips, teeth, and tongue. "Oral region" is a more general term that could include both the mouth and adjacent structures, such as the lips and cheeks. "Buccal cavity" is a term that specifically refers to the space inside the cheeks and beside the teeth. No matter which phrase is used, they all refer to the structures involved in eating and speaking.