Used to introduce some fortunate event or occurrence that benefits the person to whom one is speaking, especially when it means that they will avoid some negative outcome. A: "Oh, shoot! I forgot to bring my pencil case to the exam!" B: "Well, lucky for you, I brought several pencils with me, so you can borrow one." A: "Hi there, I'm here to check in to the flight to Paris." B: "Sir, you are nearly an hour late. Lucky for you, there has been a lengthy delay in the flight's departure, so you should still be able to make it."