Google Relateness calculates how related two words are by doing three searches. Two words have a "relatedness coefficient" of 2 if they appear together twice as often as you would expect with a total of N = 2,073,418,204 pages. Example output:

First term Second term Intersection Relatedness

To use Google Relatedness, you need the Mozilla browser and a free Google API key. After you download the zip, edit key.js so it contains your Google key.

Google Relatedness includes a JavaScript library for the Google Web APIs that was written by Eric Hodel.