What does the root "cephal/o" relate to?

The root "cephal/o" is derived from the Greek word "kephalē," which means "head." This root is commonly used in medical terminology to refer to various conditions, treatments, or anatomical references associated with the head. For example, terms like "cephalalgia" pertain to headaches, and "cephalometry" involves the measurement of the head.

In the context of the given choices, the other options do not align with the meaning of "cephal/o." Although "cephalus" might seem relevant as it sounds similar, it does not accurately reflect the root's meaning nor is it commonly used in medical terminology. The heart is indicated by the root "cardi/o," and "center" correlates with "centr/o." Therefore, the option that correctly identifies the meaning of the root "cephal/o" as "head" is the most accurate choice.