Etymology (Gk. etumos, true), a term used in philology to imply the true original sense of a word, or "the tracing out and describing the elements of a word with the modifications of form and sense." In a secondary sense it denotes the branch of philology which is connected with this. The discovery of Grimm's Law and a rigid scientific method of research have made a revolution in the science of etymology, which till comparatively late years was wildly fanciful. In grammar, etymology is that part which deals with letters and the parts of speech separately.