Which combining form indicates mouth?

• A. Kinesi/o
• B. Mandibul/o
• C. Maxilla/o
• D. Stomat/o

Answer: (D)

Combining forms pair a root with a vowel to build medical terms that connect to suffixes. The root for mouth is stomat-, and with the connecting vowel o it becomes stomat/o. This is the form you’d use when talking about the mouth itself, as in stomatitis or stomatology. The other forming stems point to different parts or concepts: kinesi/o means movement, mandibul/o refers to the mandible (lower jaw), and maxill/o to the maxilla (upper jaw). So the word element that indicates mouth is stomat/o.