A word that is printed at the top or bottom of the page in a reference work, in order to help readers find a specific entry.
A watchword; a word or phrase that serves as one's guide.
Any of the words in a memo or email that define metadata regarding the message, such as sender, recipient, and subject.
Any important word in a text or document, which may be linked to other words or other information, or at least merely listed in the metadata for searches to find.
A reserved word used to identify a specific command, function, etc.
Any word used as the key to a code.
Any word that occurs in a text more often than normal.
Any word used in a reference work to link to other words or other information.
To tag with keywords, as for example to facilitate searching.