Which prefix means 'together' or 'with'?

The prefix that means 'together' or 'with' is "sym-." In medical terminology, "sym-" comes from the Greek word "syn," which conveys the idea of things being joined together or occurring simultaneously. This prefix is often used in various medical terms to describe concepts involving unity or collaboration, such as "symbiotic," referring to organisms that live together in a close relationship, or "symptom," which indicates signs that occur cohesively as part of a condition.

The other prefixes have distinct meanings unrelated to the concept of togetherness. "Pachy-" refers to thickness, "tachy-" pertains to speed or rapidity, and "hemi-" denotes half. Understanding these distinctions helps clarify the meanings of medical terms built around these prefixes.