'CGI' originates from English, specifically as an initialism of technical phrases. Most recently it became widely used as the abbreviation of 'Common Gateway Interface' (early 1990s) and earlier as the abbreviation of 'computer-generated imagery' (late 20th century); in these phrases 'Common' meant 'shared', 'Gateway' meant 'a point of access to external programs', 'Interface' meant 'a boundary for interaction', 'computer-generated' meant 'produced by a computer', and 'imagery' meant 'visual images'.

'CGI' was formed by taking the initial letters of the multiword technical terms 'Common Gateway Interface' and 'computer-generated imagery'; the initialism quickly entered technical and popular usage in each field (web technology and visual effects) and came to be written simply as 'CGI'.

Initially, 'CGI' referred separately to specific technical concepts in different fields (web server scripting vs. computer-produced visuals); over time both senses remained in use and the initialism came to be understood contextually (web context → Common Gateway Interface; film/graphics context → computer-generated imagery).