s. 425. Derivation, like _etymology_, is a word used in a wide and in a limited sense. In the wide sense of the term every word, except it be in the simple form of a root, is a derived word. In this sense the cases, numbers, and genders of nouns, the persons, moods, and tenses of verbs, the ordinal numbers, the diminutives, and even the compound words, are alike matters of derivation. In the wide sense of the term the word _fathers_, from _father_, is equally in a state of derivation with the word _strength_, from _strong_. In the use of the word, even in its limited sense, there is considerable laxity and uncertainty. _Gender, number, case._--These have been called the _accidents_ of the noun, and these it has been agreed to separate from derivation in its stricter sense, or from derivation properly so called, and to class together under the name of declension. Nouns are declined. _Person, number, tense, voice._--These have been called the accidents of a verb, and these it has been agreed to separate from derivation properly so called, and to class together under the name of conjugation. Verbs are conjugated. Conjugation and declension constitute inflection. Nouns and verbs, speaking generally, are inflected. Inflection, a part of derivation in its wider sense, is separated from derivation properly so called, or from derivation in its limited sense. The degrees of comparison, or certain derived forms of adjectives; the ordinals, or certain derived forms of the numerals; the diminutives, &c., or certain derived forms of the substantive, have been separated from derivation properly {368} so called. I am not certain, however, that for so doing there is any better reason than mere convenience. By some the decrees of comparison are considered as points of inflection. Derivation proper, the subject of the present chapter, comprises all the changes that words undergo, which are not referable to some of the preceding heads. As such, it is, in its details, a wider field than even composition. The details, however, are not entered into. s. 426. Derivation proper may be divided according to a variety of principles. Amongst others, I. _According to the evidence._--In the evidence that a word is not simple, but derived, there are at least two degrees. A. That the word _strength_ is a derived word I collect to a certainty from the word _strong_, an independent form, which I can separate from it. Of the nature of the word _strength_ there is the clearest evidence, or evidence of the first degree.