A path is a directory specification. In other words, it tells you where something is located on your hard drive. Linux has a directory hierarchy that begins at /, which is also known as 'root'. (Take care to note that this is a FORWARD slash, not a backslash.)
In the / (root) directory, you'll find several standard directories like /bin, /usr, and /home. When a path starts at /, with something such as /home/username/public_html, it is known as an absolute path.