Book 5
1
Element means (a) the primary immanent thing, formally indivisible into another form, of which something is composed. E.g., the elements of a sound are the parts of which that sound is composed and into which it is ultimately divisible, and which are not further divisible into other sounds formally different from themselves. If an element be divided, the parts are formally the same as the whole: e.g., a part of water is water; but it is not so with the syllable.
2
(b) Those who speak of the elements of bodies similarly mean the parts into which bodies are ultimately divisible, and which are not further divisible into other parts different in form. And whether they speak of one such element or of more than one, this is what they mean.
3
(c) The term is applied with a very similar meaning to the elements of geometrical figures, and generally to the elements of demonstrations; for the primary demonstrations which are contained in a number of other demonstrations are called elements of demonstrations.Cf. Aristot. Met. 3.3.1. Such are the primary syllogisms consisting of three terms and with one middle term.
4
(d) The term element is also applied metaphorically to any small unity which is useful for various purposes; and so that which is small or simple or indivisible is called an element.
