D defs.my
Entry 2 senses Webster, 1913

Autumnal

/ôt-ŭm'-nəl/ · Au·tum·nal · IPA /ɔːˈtʌm.nəl/
01 a. Of, belonging to, or peculiar to, autumn; as, an autumnal tint; produced or gathered in autumn; as, autumnal fruits; flowering in autumn; a…
  1. 1.
    Of, belonging to, or peculiar to, autumn; as, an autumnal tint; produced or gathered in autumn; as, autumnal fruits; flowering in autumn; as, an autumnal plant.
    “Thick as autumnal leaves that strow the brooks In Vallombrosa.” Milton.
  2. 2.
    Past the middle of life; in the third stage.
    “An autumnal matron.” Hawthorne.
Phrases & compounds
Autumnal equinox — the time when the sun crosses the equator, as it proceeds southward, or when it passes the autumnal point.
Autumnal point — the point of the equator intersected by the ecliptic, as the sun proceeds southward; the first point of Libra.
Autumnal signs — the signs Libra, Scorpio, and Sagittarius, through which the sun passes between the autumnal equinox and winter solstice.