Final answer:
In medical terminology, the word part mento- refers to the chin, as exemplified by terms such as 'mental protuberance' and 'mental foramen,' which are associated with the structure and sensory supply of the chin.
Step-by-step explanation:
The word part mento- in medical terminology is associated with the chin. This is evidenced by the term mental protuberance, which refers to the forward projection from the inferior margin of the anterior mandible that forms the chin. Additionally, the mental foramen is an opening located on the anterior-lateral side of the mandibular body, serving as the exit point for a sensory nerve that supplies the chin area. Therefore, based on the provided information, the correct answer to the question 'the word part mento- means' is (a) chin.