Definition - What does Theme mean?
In computing, a theme is a visual pattern or collection of patterns that determines the look and feel of a graphic interface. Themes are applied to just about any computer program that relies heavily on graphic elements, such as a browser, software program or operating system. Themes incorporate both practical and stylistic considerations.
Techopedia explains Theme
Themes have been part of digital computing since the earliest graphic interfaces. The SAGE (Semi-Automatic Ground Environment) Project is said to have developed one of the original multi-panel window systems in their real-time graphic environments, which was important to the gradual development of the thematic visual interface.
Decades later, Apple Computers became notable for their early desktop themes within their personal computer operating systems – a trend that has persevered in personal computing for decades. This established many file organization visual metaphors (such as folders) that have become very familiar to users over the years.