The term "Yo-Yo" has multiple meanings depending on its context.
1) It can refer to a popular toy consisting of two discs connected by an axle, which is spun between one's fingers and thrown outwards so that it returns to the hand due to the rotation of the axle. This type of yo-yo has been around for centuries and is still enjoyed today as both a recreational activity and a competitive sport.
2) It can also refer to a slang term used in texting or online communication, meaning "you are" or "yours truly." For example: "Yoyo just got back from vacation!" would mean that the person being referred to went on vacation recently.