"OUO" is a slang term used in online chatting or texting, which represents the expression of a surprised or shocked face. The spelling of this word is represented in IPA phonetic transcription as /oʊju oʊ/. It is pronounced as oh-yoo-oh, with a stress on the first syllable. The combination of the letters "O - U - O" represents the two vowels "O" and "U" with consonant "O" in between, which reflects the facial expression of someone with their mouth and eyes wide open.