A Rating column type is used to enter a rating like a rating of a movie or a restaurant. When you double click on the cell, you get the option to rate from 0-5 and it appears as stars by default.
The icon and the color of the Rating can be changed by clicking the style option in the properties and then selecting the desired icon and color as well as the maximum value of Rating can also be changed.
The sort option can be used to sort the rows from first to last or last to first based on the value of this column. Read more about sort here.