Thayer's Greek-English Lexicon is a translation and revision of C.G. Wilke's / C.L. Wilibald Grimm's Clavis Novi Testamenti. Thayer worked nearly thirty years on the English translation. During that time he added thousends of revisions based on newer Greek scholarship. Thayer's provides dictionary definitions for each word and relates each word to its New Testament usage and categorizes its nuances of meaning. Its exhaustive coverage of New Testament Greek words, as well as its extensive quotation of extra-biblical word usage and the wealth of background sources consulted and quoted, render Thayer's an invaluable resource.