Eu

Eu Eu [Gr. e'y^ well, orig. neut. of e'y`s good; prob. connected with Skr. su, from the same root as E. is; or with Skr. vasu good, prob. fr. the same root as E. was.] A prefix used frequently in composition, signifying well, good, advantageous; -- the opposite of dys-. [1913 Webster]