-ius

-i--us lat. dt. "-lich, -ich, -ig, -ern ..."

Pronunciation

• (Classical) IPA^(key): /i.us/, [iʊs̠]
• (modern Italianate Ecclesiastical) IPA^(key): /i.us/, [ius] (stressed on the antepenult)

Etymology 1

From Old Latin -ios, from Proto-Italic *-jos, from Proto-Indo-European *-yós.

Suffix

-ius (feminine -ia, neuter -ium); first/second-declension suffix

1. forming adjectives from nouns
2. (New Latin) suffix for Latinizing surnames

Usage notes

The suffix -ius is added to a noun to form an adjective indicating "made of" or "belonging to" that noun.

Examples:

‎pater (“father”) + ‎-ius → ‎patrius (“paternal”)

‎rēx (“king, ruler”) + ‎-ius → ‎rēgius (“kingly, royal”)

‎uxor (“wife”) + ‎-ius → ‎uxōrius (“uxorious”)

‎papȳrus (“papyrus”) + ‎-ius → ‎papȳrius (“made of papyrus”)

In taxonomics, out of analogy with ancient Roman cognomina, this suffix is added to surnames ending in a consonant other than the ending -er and, sometimes, replacing a mute final -e.

Examples:

‎French Descartes + ‎-ius → ‎Cartesius

‎German Leibniz + ‎-ius → ‎Leibnitius

‎German Schmalz + ‎-ius → ‎Smalcius

‎English Shakespeare + ‎-ius → ‎Shakespeārius

Declension

First/second-declension adjective.

Number	Singular				Plural
Case / Gender	Masculine	Feminine	Neuter		Masculine	Feminine	Neuter
Nominative	-ius	-ia	-ium		-iī	-iae	-ia
Genitive	-iī	-iae	-iī		-iōrum	-iārum	-iōrum
Dative	-iō		-iō		-iīs
Accusative	-ium	-iam	-ium		-iōs	-iās	-ia
Ablative	-iō	-iā	-iō		-iīs
Vocative	-ie	-ia	-ium		-iī	-iae	-ia