kwic

KWIC stands for Key Word In Context. It is a type of concordance index used in linguistics, lexicography, and information retrieval. In a KWIC index, every occurrence of a chosen keyword or phrase in a text corpus is shown together with surrounding context, and the entries are arranged alphabetically by the keyword.

How it works: a corpus is scanned to locate each occurrence of the target terms. For each occurrence, a window of surrounding words on the left and right is captured. The line is typically formatted with the keyword near the center, flanked by the left and right context, and the lines are sorted by the keyword.

Origins and related concepts: KWIC emerged with the development of computer-assisted concordancers in the mid- to late 20th century as a tool for studying word usage. Related indexing approaches include KWOC (Key Word Out of Context), which lists headwords alphabetically with successive contexts, but without centering the keyword.

Applications and limitations: KWIC is used in lexicography, corpus linguistics, and search interfaces to examine polysemy, collocations, and usage patterns. Its usefulness depends on choices such as the window size, tokenization, and handling of morphological variants; large corpora can yield extensive outputs that require filtering and analysis.