What is the difference between single forward slash and double forward slash in XML Path Language (XPath)?

In XPath, a single forward slash (/) is used to select nodes at a specific level from the root of the document, creating an absolute path. A double forward slash (//) is used to select nodes anywhere in the document that match the specified criteria, regardless of their position. This makes // a more flexible and often preferred operator for locating elements when their exact hierarchical position isn't critical or known.