What does descriptor mean?
A descriptor is a word, phrase, or label that conveys information about the nature or identity of something else. The term is most at home in technical and academic settings: librarians and information scientists use descriptors as standardized terms for classifying documents, linguists use them to characterize grammatical features, and programmers rely on descriptors as structured records that describe system resources — most famously the file descriptor, a small integer that lets a program refer to an open file. Outside these fields, the word simply denotes any descriptive tag attached to data, from image captions to database keywords. Because it signals precision and systematic classification, descriptor carries a formal, professional tone; casual conversation favors plainer alternatives like label or tag. Derived from the Latin verb describere, meaning to write down or copy, it entered English as a noun of agency, literally 'something that describes.' Its usefulness lies in naming the act of characterization itself — a handy word whenever one thing must be identified by what it says about another.
A word, phrase, or label that describes or identifies something.
"'Coastal' serves as a useful descriptor for the region's climate."
Common in indexing, cataloguing, and metadata contexts.
In computing, a data item or handle containing information about another resource, such as an open file or memory block.
"The kernel assigns a file descriptor each time a process opens a file."
Standard plural; regular -s formation.
"The index lists all the subject descriptors assigned to each article."
Every file on your computer is quietly introduced to the operating system by a numbered business card called a file descriptor — open too many at once and even your programs get overwhelmed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of descriptor
Descriptor derives from the Latin verb describere, meaning 'to write down, copy, or sketch,' formed from de- ('down, away') plus scribere ('to write'). English borrowed the agentive pattern directly, so a descriptor is literally 'that which describes.' It developed alongside its siblings description and descriptive, all sharing the scribere root that also gives us scribe, script, and inscribe. Its modern technical senses — especially in information science and computing — emerged in the twentieth century as classification systems and operating systems required precise terminology.
How descriptor is actually used
Descriptor is largely formal and technical, common in library science, information retrieval, linguistics, and computing. In everyday speech people usually say label, tag, or keyword instead. In computing contexts it often appears in fixed compounds like file descriptor.
Easily confused with descriptor
A description is the full account or depiction of something, while a descriptor is a single term or label used to characterize it.