Ace the CPO Exam 2026 – Shine Bright as a Certified Paraoptometric Star!

The prefix that is used to indicate opposition or hostility in medical terminology is indeed "Anti-." This prefix is derived from Greek, meaning "against" or "opposite to." It is commonly used in various medical terms to denote resistance or opposition to something, particularly in contexts such as "antibiotic" (against life, referring to bacteria) or "antihistamine" (against histamines). This understanding is essential in medical contexts to clearly express the action or effect relating to opposition, making "Anti-" the correct choice in this instance.