What are WordPress themes?
WordPress themes are set of files that altogether work and provide a nice and attractive graphical interface on the blogs and the websites. Basically these are huge collection of various files which controls and manages the appearance and the functionality of the website. Refer to websites like http://yoctotemplates.com/category/wordpress-themes/ and you will be able to figure out the difference.
According to WordPress.org, themes are collections of files “that work together to produce a graphical interface with an underlying unifying design for a weblog.” In layman’s terms, a WordPress theme is what controls the functionality, the look, and the feel of a WordPress website. WordPress themes come in a variety of flavors, from basic, free themes to more complex, premium themes. The key takeaway about WordPress themes any beginner must know is that at any moment a WordPress website’s theme may be changed without adversely affecting the actual content of the website.