I was wondering whether anyone knows the exact difference between the English suffixes -agenous and -aginous.

I believe the difference is that the first suffix has to do with describing the rough essence of what something is made up of from a physical or physics standpoint, whereas the second suffix seems more heard towards describing personal character.

However, I am not sure whether this is the right distinction. I would also like to know whether there is an online etymological dictionary resource which deals with, preferably exclusively, with such suffixes, prefixes, and possibly also infixes to the extent that infixes may exist in English (personally, I am not aware of any or never studied any in English).

Thank you for your feedback.

  • Some examples of words with your chosen suffixes would be a good part of your research to reproduce in the question.
    – Nigel J
    Commented May 20, 2018 at 10:45
  • 1
    The full OED has a listing for the suffix -genous, defined as Forming adjectives with the meaning: ‘of, pertaining to, or relating to generation or production’. It has no such entry for -ginous, and to be honest I don't think this is or ever was a "productive suffix" in English. The only words I know based on it are oleaginous and vertiginous. Commented May 20, 2018 at 11:54

1 Answer 1


The a in -agenous and, in the vast majority of cases, the -agin in -aginous are part of the word to which the the suffix -ous is added to make an adjective. These are not English suffixes, but Latin or Greek, though they may appear in English words with origins in those ancient languages and could still form new words today.

x + gen + ous

Further dissecting -genous yields -gen, from Greek -γεvής (-genēs), which means produced by or producing whatever the first element is. Think gene, generate, even genitals if you’re so inclined. “Element” is sometimes quite literal: hydrogen (1791), oxygen (1790), nitrogen (1794), halogen (1842) which, at least etymologically, generate water, acid (Gk. oxys), baking soda (Gk. nitron), and salt (Gk. hals). These names were all coined by French chemists shortly before their adoption into English.

You can form adjectives simply by adding -ous: hydrogenous, oxygenous, nitrogenous, halogenous. These words are accented on the antepenultimate, i. e., third from the last syllable.

Another example:

Gk. κόλλα, ‘glue’ > Latinized, colla > (Fr. collagène ) > collagen > collagenous

x + in + ous

Latin adjectives are commonly formed from the oblique cases of nouns. In third declension nouns in -go, that means adding -in to the root before the morphological ending. The -go itself is a suffix, though it is not always clear what the root is:

Lat. cartilago ‘cartilage’, genitive: cartilaginis > cartilaginos -us, -a, -um > (Fr. cartilagineux) = cartilaginous

With these two words, the root is clear:

Lat. mucus > mucere, ‘be moldy, musty’, Late, Med. Lat. mucilago, mucilagin-, ‘viscous, sticky liquid from plants’> (Old French mucilage) > mucilage > mucilaginous

Lat. ferrum, ‘iron’ > ferrugo, ferrugin-, ‘rust or its color’ > ferruginous

In contrast to more recent scientific words, oleaginous entered English already in the early 15th c.

olea, oleæ (!), ‘olive’ > Med. Lat. oleagin -us, -a, -um > OFr oléagineux > oleaginose > (from 1630s) oleaginous, ‘oily, like oil; unctious’.

Although olea is not a third declension noun but first, the medieval adjective treats it as one. For English, of course, that is of little importance, since the word was simply Englished from Old French.

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