From key + word.

• (RP) IPA: /ˈkiː.wɜːd/
• (America) IPA: /ˈki.wɝd/

keyword (plural keywords)

1. (cryptography) Any word#Noun used as the key to a code.

   Synonyms: password, passcode

   Coordinate term: keyphrase

2. (information science) Any word#Noun used in a reference work to link to other words or other information.
3. (information science) Any important word#Noun in a text#Noun or document, which may be linked to other words or other information, or at least merely listed in the metadata for searches to find.

   Synonyms: operative word, workword

   Hypernyms: keystring

   Coordinate term: keyphrase

4. (programming) A reserved word used to identify a specific command, function etc.
   • 2017, Wisnu Anggoro, Learning C++ Functional Programming, page 8:

     Since C++11, the auto keyword is used to tell the compiler to deduce the actual type of a variable that is being declared from its initializer.

5. (linguistics) Any word that occurs in a text more often than normal.

   Coordinate terms: collocation, statistically improbable phrase

• French: mot-clé
• German: Schlüsselwort, Passwort, Stichwort
• Italian: parola chiave
• Portuguese: palavra-chave
• Russian: ключево́е сло́во
• Spanish: palabra clave, clave

• German: Stichwort
• Russian: ключево́е сло́во

• German: Schlüsselwort

keyword (keywords, present participle keywording; simple past and past participle keyworded)

1. (transitive) To tag with keywords, as for example to facilitate searching.