The phrase "what do you mean?" is commonly used to ask someone to clarify their statement or intention when it seems unclear or contradictory. It is also the title of a popular song by Canadian singer Justin Bieber released in 2015. In the song, the phrase is repeated to express confusion about mixed signals in a relationship, such as when someone nods yes but seems to mean no, or says one thing but acts in an opposite way. The song explores themes of indecision and mixed messages between partners and asks for clarification to understand the true meaning behind their actions and words.