I’ve found that the term “sidebar” within WordPress can have multiple meanings. Within your index.php file you will most likely find a call to the php function get_sidebar(). This is referring to the sidebar column, sometimes called the right-hand (or left-hand) navigation column. A sidebar also refers to the location where you add all your Widgets. The Widgets control the content that appears within the sidebar (column) and will usually display lists such as your Recent Posts, Categories, Links or dozens of other items.