Keyword

In computer science, a keyword is an identifier which indicates a specific command. Many times the keyword is restricted to that core language usage, in which case it is also considered a reserved word. Some common keywords in many programming languages are: else, end, goto, if, print, return, switch, then, while, etc. There are usually restrictions about reusing keywords as names for user-defined objects such as variables or procedures, however some languages are extremely liberal in this approach (such as PostScript), allowing core keywords to be redefined for specific purposes. Languages vary as to what is provided as a keyword and what is a library routine, for example some languages provide keywords for input/output operations whereas in others these are library routines.
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A keyword is a featured word of a technical article. Some publications specify a fixed set of keywords from which those for a particular article should be chosen.
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In corpus linguistics a keyword is a word which occurs in a text more often than we would expect to occur by chance alone. Keywords are calculated by carrying out a statistical test (e.g. loglinear) which compares the word frequencies in a text against their expected frequencies derived in a much larger corpus, which acts as a reference for general language use. Mike Scott's corpus analysis tool WordSmith can automatically calculate keywords.
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In Information Retrieval (aka searching) a keyword is a word or phrase which describes a concept found, but not necessarily explicitly named, in a document. This is what your library catalog means by keyword.

References

Supplier of established Key Word Domain Names & WebSites

External Links