(1) A specialized processor, such as a graphics processor. Like any engine, the faster it runs, the quicker the job gets done. See
graphics engine and
printer engine.
(2) Software that performs a very specific and repetitive function in contrast to an application that has many functions offered to the user. For example, a "search engine" or "database engine" responds to user queries over and over again. An "SMTP engine" forwards mail. A "dictionary engine" looks up words. A "rendering engine" forms the text and images that are displayed and printed. See
search engine,
database engine and
rendering engine.