What is the combining form for breast commonly used in medical terminology?

The combining form for breast that is most commonly used in medical terminology is "mamm/o." This term originates from the Latin word "mamma," which means breast. It is frequently used in medical contexts related to breast health, such as in the terms "mammogram" (an X-ray of the breast) and "mammoplasty" (surgical modification of the breast).

While "mast/o" is also a valid combining form that refers to the breast and can be seen in terms like "mastitis" (inflammation of the breast), "mamm/o" is more widely recognized in standard terminology. The other combining forms listed are associated with entirely different body systems: "gastr/o" pertains to the stomach, and "hem/o" refers to blood, thus they are not relevant to the breast.