Noun
moo-moo (plural moo-moos)
(childish) A cow.
moo-moo (plural moo-moos)
Alternative form of muumuu
Who did you eat this time? (Acheron) It wasn't a who, akri. It was something that had hornies on its head like me. There were a bunch of them actually. All of them had hornies and they made a strange moo-moo sound. (Simi) Sherrilyn Kenyon
This fall, Abrams will publish a new book the pair had left unfinished at the time of Rosenthal’s death: “Moo-Moo, I Love You!” Source: Internet