-atus

From Proto-Italic *-ātos, from Proto-Indo-European *-eh₂tos. A "pseudo-participle" possibly related to -tus, though similar formations in other Indo-European languages show that it was distinct from it already in Indo-European times.

Cognate to Proto-Slavic *-atъ, Proto-Germanic *-ōdaz (English -ed (“having”)).

-ātus m (feminine -āta, neuter -ātum); first/second declension

1. -ed, -ate, -like. Used to form adjectives from nouns indicating the possession of a thing or a quality.

   barba (“beard”) → barbātus (“bearded, having a beard”)

   rēticulum (“small net”) → rēticulātus (“reticulated, net-like”)

   albus (“white”) → albātus (“clothed in white”)

First/second declension.

• -āticus, -āticum
• -ātim
• -ātiō

By rebracketing of action nouns in -tus, -tūs formed from first conjugation verbs, such as mercātus (mercor + -tus) or pecūlātus (peculor + -tus), where -ā- is actually part of the stem.

-ātus m

1. Form of -tus appended to nouns

   ‎triumvir + ‎-ātus → ‎triumvirātus

   ‎episcopus + ‎-ātus → ‎episcopātus

   ‎apostolus + ‎-ātus → ‎apostolātus

Fourth declension.

• French: -at