annus

Annus is a Latin noun meaning year, used to designate a calendar year or a duration of time. It is masculine and belongs to the second declension. In Latin, it appears in phrases such as anno Domini (in the year of the Lord) and per annum (by the year/each year), and its forms appear in both classical and ecclesiastical texts.

Declension

Singular:

- Nom. annus

- Gen. anni

- Dat. anno

- Acc. annum

- Abl. anno

Plural:

- Nom. anni

- Gen. annorum

- Dat. annis

- Acc. annos

- Abl. annis

Usage and derivatives

In Latin, annus can denote either a specific year in a dating system or a span of years when used with appropriate modifiers. The ablative form anno is common in temporal expressions such as “anno Domini” or “anno salutis.” The genitive singular anni often appears in phrases indicating possession or duration.

The term has given rise to several English and Romance-language derivatives. English phrases such as per annum (per year) and annual (occurring every year) descend from annus. The root also appears in Latinized phrases like annus mirabilis (a remarkable year) and annus horribilis (a disastrous year), which have entered common English usage in literary or formal contexts. In Romance languages, cognates include Italian anno, French année, and Spanish año, reflecting the same root.

Overview

Annus serves as the classical basis for modern terms related to yearly cycles, calendars, and periodicity, and appears in both historical dating and modern linguistic products. It remains a standard reference in discussions of Latin grammar, historical dating, and etymology.