-gencomb. form

1. Chemistry. In 1777–9 Lavoisier ( Œuvres II. 249) proposed for the recently discovered element (till then known as ‘dephlogisticated air’, etc.) the alternative names principe acidifiant and principe oxygine, which he states to be etymologically synonymous. In G. de Morveau Nomencl. chimique 1787 (prepared in collaboration with Lavoisier and other chemists) the nouns oxygène and hydrogène occur, and are explained to mean ‘engendrant l'acide’ and ‘engendrant l'eau’; and in Lavoisier's Traité de Chimie 1789 the etymon of the suffix is said to be ‘Greek γείνομαι, j'engendre’. This etymology accounts for Lavoisier's original form oxygine; the change of -gine into -gène must have been due to the observation that -gine did not occur in Greek derivatives, while -gène, from the same root, already existed in hétérogène, homogène ( < Greek words in -γενής: see above); the fact that the suffix -γενής in Greek words was not capable of meaning ‘that which produces’ was overlooked or disregarded. The names oxygène, hydrogène were soon adopted into English with the ending -gene, afterwards altered to -gen. On the analogy of these words, a considerable number of new terms have been added to the common (French and English) vocabulary of chemistry, in which the ending -gène, -gen expresses the sense ‘that which produces’; they are usually names of chemical substances, as nitrogen, amidogen, cyanogen, etc.; rarely of classes of substances, as halogen, †amphigen.

2. Botany. The botanical use of -gène was introduced in 1813 by Decandolle ( Théorie de Botanique 210) in the words endogène, exogène, adjectives designating two classes of plants which respectively produce their new tissue internally (Greek ἔνδον within) and externally (Greek ἔξω outside). The formation of the words was suggested by the older terms endorhize, exorhize. Decandolle gives as the etymon of the suffix ‘γεναω [sic!], j'engendre, je crois’; apparently his -gène was not a new adoption from Greek -γενής, but a different application of the -gène already used in chemical terms, which he vaguely remembered to be derived from a Greek root meaning ‘to produce, to grow’. The adjectives endogène, exogène first came into English in the adapted forms endogenous, exogenous; Lindley c1845 formed from these the nouns endogen, exogen; and he and others added many analogous terms denoting classes of plants, the first element indicating the part at which the new growth takes place, or some characteristic of their mode of growth, as acrogen, amphigen, dictyogen, thallogen. The suffix is also occasionally used in terms denoting plant tissues that give rise to particular kinds of cells, as calyptrogen, dermatogen, phellogen.

3. Geology. In the form -gene, used in terms indicating the type, method, or place of formation, as tectogene.