LATIN DICTIONARYLexicon Latīnum
suffix · masculine

-ior

-ior m or f (neuter -ius)
Classical[i.ɔr]Ecclesiastical[i.or]

Meaning

  1. femininemasculinemorphemeforms adjectives’ comparative degrees
    esculentus → esculentior
    pūtidus → pūtidior

Origins

From Proto-Italic *-jōs, from Proto-Indo-European *-yōs, for original **-yoss, i.e. the s-stem *-yos- with masculine nominative *-s. The ō from the nominative case was made common to all cases. Afterwards nom.sg. -iōr > -ior, by Latin sound laws. Thus paradoxically, as in the r-stems (soror, -tor, -or), in the resulting paradigm the one form with a short stem vowel is the only form whose stem was etymologically long.

Quick answers

What does -ior mean in Latin?
-ior, a suffix, means “forms adjectives’ comparative degrees”.
How do you pronounce -ior?
In classical Latin, [i.ɔr]; in ecclesiastical (church) Latin, [i.or].