Appendix:Latin fourth declension

Description

Latin words of the fourth declension are generally masculines or, less commonly, feminines in -us and neuters in -ū. The genitive is in -ūs.

The dative-ablative plural -ibus may appear less commonly as -ubus.

Examples

Masculine or feminine -us form

Case	Singular	Plural
nominative	-us	-ūs
genitive	-ūs	-uum
dative	-uī	-ibus
accusative	-um	-ūs
ablative	-ū	-ibus
vocative	-us	-ūs

Examples:

• manus f
• cursus m

Neuter -ū form

Case	Singular	Plural
nominative	-ū	-ua
genitive	-ūs (-ū)	-uum
dative	-ū (-ūī)	-ibus
accusative	-ū	-ua
ablative	-ū	-ibus
vocative	-ū	-ua

Examples:

• cornū, -ūs (-ū) n

Feminine -ō form (from Greek)

Nouns derived from Greek feminine proper nouns in -ω (genitive -ους).

19th-century grammars often treat this type under the third declension, and alternative third-declension Latin suffixes are attested for some (e.g. Callistōnem). The distinction is no longer seen as salient, but classifying the otherwise indeclinable paradigm with genitive in -ūs as fourth-declension is consistent with the general practice of distinguishing declension based on the genitive singular ending.

Examples of this category: Aëllō, Allēctō (Alēctō), Argō, Brīmō, Callistō, Calypsō, Celaenō, Cētō, Chariclō, Clīō, Clōthō (Clōtō), Dīdō, Drȳmō, Ēchō, Enȳō, Eratō, Erichthō, Hērō (Erō), Īō, Īnō, Lātō, Lētō, Mantō, Melanthō, Pērō, Polyxō, Pȳthō, Sapphō, Theānō, Tȳrō, Xanthō

Citation form: ēchō, ēchūs f

Case	Singular
nominative	ēch-ō
genitive	ēch-ūs
dative	ēch-ō
accusative	ēch-ō
ablative	ēch-ō
vocative	ēch-ō

Note: The accusative can also end in -ūn or -ōn, like Dīdō with accusative Dīdūn.

See also

• Latin first declension
• Latin second declension
• Latin third declension
• Latin fifth declension
• Wikipedia article on declension
• Wikipedia article on Latin declension