Serendipity is a nice way of saying something really lucky happened to you. It's like when you are looking for your favorite toy and you find it under the couch - it was a serendipity because it's something special and unexpected. Serendipity can also happen when you are trying to find something else and you find something new that you didn't know you could use. It's like when you go on a walk and see a beautiful flower you have never seen before. For adults, serendipity can help them solve problems or find new ideas - like when two scientists accidentally combine two things and invent something new.