The official greeting regarding the moon folks, as defined by players of NASA's online game Moonbase Alpha.Commonly utilized a a greeting, proclamation of happiness, or exclamation.Pronounced "aye-yoo". (pron. AY-oo)1. The typical set of vowels inside Latin alphabet.2. An uncommon way of saying "Hey, you" Noun; AYE-yoo; The feeling of real curiousity which encourages at a first encounter - a predecessor to an infatuation.