“on both sides,” “around” — directional/quantitative prefix
The word entered English in the 1600s as amphi- (prefix), borrowed from Late Latin amphi-, from Greek amphà — literally “on both sides.” The root amphi (“both”) connects amphi- to the entire dual-directional roots: amphibian (amphi- + bios → living on both land and water), amphoteric (amphi- + ergon → acting in both ways/acid-base), and amphitheater (around the theater). The directional prefix amphi- is productive in medical and biological terminology: e.g., amphioxus, amphigamy, and amphidromic.