Relative Paths
A relative path is a path that describes the location of a file or folder in relative to the current working directory. It can be best used to refer to websites that are located on the same domain, ideally on certain sections of websites in which the documents never change relationships to each other. Unlike absolute paths, relative paths contain information that is only relative to the current document within the same website.
Absolute Paths
An absolute path is a path that describes the location of a file or folder relative to the root directory. It contains the complete location of a file or directory. Absolute paths contain all the relevant information to find the resources indicated by an absolute URL. An absolute path must be used to refer to websites that are on a domain other than your home domain.
Why is it important?
Relative paths and absolute paths help you keep your website organized and structured properly.
Visuals

Resources: http://www.differencebetween.net/technology/difference-between-absolute-and-relative-path/
Definitions to help me understand:
root directory: is the top-level directory of a file system








