pon·zu (pŏn'zōō') n. A Japanese sauce typically made from mirin, rice vinegar, bonito flakes, a citrus juice, and sometimes soy sauce, often used as a condiment for seafood.
[Japanese, alteration (influenced by -zu, combining form of su, vinegar) of ponsu, mixed drink containing citrus juice, ponzu, from Dutch pons, punch, from English punch3.]