Google ngram ViewerWhen you enter phrases into the Google Books Ngram Viewer, it displays a graph showing how those phrases have occurred in a corpus of books (e.g., "British English", "English Fiction", "French") over the selected years.
"When applied to linguistic analysis, natural language processing, and text generation, an n-gram is, typically, a phrase composed of “n” that is “one or more” “grams” that are “tokens” (in the parlance of algorithmic parsing) or “words” (for our purposes)."
See: Cayley, John. "N- gram." The Johns Hopkins Guide to Digital Media, Marie-Laure Ryan, et al., Johns Hopkins University Press, 1st edition, 2014. Credo Reference.