What prefix means self?

The prefix that means "self" is "Aut/o." This prefix comes from the Greek word "autós," which translates to "self." It is commonly used in medical terminology to signify something that is self-driven or self-generated. For example, in terms like "autonomy," "autonomous," or "autoimmune," the "aut/o" prefix clearly indicates a relationship to the self or self-regulation.

In contrast, the other prefixes have different meanings: "Bi/o" refers to life or living organisms; "Caus/o" relates to cause or originating principles; and "Adip/o" pertains to fat. Each of these prefixes serves distinct roles in medical terminology but does not convey the notion of self as clearly as "Aut/o" does. This makes "Aut/o" the correct choice for the prefix meaning "self."