In the Python programming language a descriptor is "an object attribute with 'binding behavior', one whose attribute access has been overridden by methods in the descriptor protocol." ^[1] For example a descriptor can be used to prevent setting the radius attribute of an object representing a circle to a negative value or to log all access or changes to a specific attribute.

A descriptor in Symbian OS is a text string. There is a library of descriptor classes incorporating all the usual string manipulation methods. Descriptors come in two main types, 8 bit and 16 bit. An 8 bit descriptor stores ASCII text or binary data, a 16 bit descriptor stores Unicode text.

In information retrieval a descriptor is an index term. The term was coined by Calvin Mooers in 1948.

In operating systems, a file descriptor is an abstract key for accessing a file.

In x86 architecture, the segment descriptor