In computer science, a tagged pointer is a pointer with additional data associated with it, such as an indirection bit or reference count. This additional data is often "folded" into the pointer, meaning stored inline in the data representing the address, taking advantage of certain properties of memory addressing. The name comes from "tagged union", and the additional data is called a "tag" or "tags", though strictly speaking "tag" refers to data specifying a type, not other data; however, the usage "tagged pointer" is standard.