What does "autumnal" mean?

Autumnal: Past the middle of life; in the third stage. An autumnal matron. Hawthorne. Autumnal equinox, the time when the sun crosses the equator, as it proceeds southward, or when it passes the ~ point. -- ~= point, the point of the equator intersected by the ecliptic, as the sun proceeds southward; the first point of Libra. -- ~= signs, the signs Libra, Scorpio, and Sagittarius, through which the sun passes between the ~ equinox and winter solstice.