From WordNet (r) 3.0 (2006) :
descriptor
n 1: the phonological or orthographic sound or appearance of a
word that can be used to describe or identify something;
"the inflected forms of a word can be represented by a stem
and a list of inflections to be attached" [syn: form,
word form, signifier, descriptor]
2: a piece of stored information that is used to identify an
item in an information storage and retrieval system
From The Free On-line Dictionary of Computing (30 December 2018) :
descriptor
An integer, string or other small data
value which refers to one of several objects allocated to a
program by the operating system, usually the kernel. A
common example is a Unix file descriptor which is a small
integer that identifies an I/O channel. Another example is a
reference to an area of memory (e.g. shared memory).
Compare capability.
(1998-02-06)