What do you know? Definition 1 of 4Pro Tip 1/3Emotional Intonation Used with a rising intonation to genuinely express surprise. What do you know! They're getting married! Pro Tip 2/3Expressive Punctuation Followed by an exclamation point to convey excitement or shock. What do you know! This place is just how I remembered it! Pro Tip 3/3Casual Conversation Commonly used in informal chats where sharing news can cause astonishment. What do you know, she's moving to Spain!