#classical Latin
- Ambarvalia — Ancient Roman agricultural festivals celebrated annually in May in honor of Ceres and Mars, consisting of a ceremonial procession of sacrificial animals around the boundaries of the fields to purify the land and ensure crop fertility.
- Aquilinum — A Latin specific epithet used in botanical taxonomy, most frequently in the binomial name of the bracken fern (Pteridium aquilinum); the term refers to the structural resemblance of the stem's cross-section or the shape of the fronds to an eagle's wings or talons, describing plants with a global ecological distribution.
- Argonautae — The original Latin plural form for the Argonauts; a designation used in Roman classical texts, ancient poetry (such as the works of Valerius Flaccus), and older scholarly or taxonomic treatises to denote the collective group of mythological sailors who accompanied Jason in his quest for the Golden Fleece.