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.

Masculine or feminine -us form
Examples:
 * manus
 * cursus

Neuter -ū form
Examples:
 * cornū, -ūs (-ū)

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. ). 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:, , , , , , , , , ,  , , , , , , ,  , , , , , , , , , , , , ,

Citation form: ēchō, ēchūs

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