Eu

·- A prefix used frequently in composition, signifying well, good, advantageous;

— the opposite of dys-.

eu
eu, interj., = εὖ, well! well done! bravo! an exclamation of joy or approbation, Plaut. Most. 1, ...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
eu
eu interj., εὖ, bravo! well! well done!: Eu noster, laudo, T.: ‘eu!’that's right, H. ...

An Elementary Latin Dictionary