What is "vernal signs"

Vernal \Ver"nal\, a. [L. vernalis, fr. vernus vernal, ver spring; akin to Gr. ?, Skr. vasanta, Icel. v[=a]r, and E. Easter, east.]

1. Of or pertaining to the spring; appearing in the spring; as, vernal bloom.

2. Fig.: Belonging to youth, the spring of life.

   When after the long vernal day of life.
   --Thomson.

   And seems it hard thy vernal years Few vernal joys can show?
   --Keble.

   Vernal equinox (Astron.), the time when the sun crosses the equator when proceeding northward.

   Vernal grass (Bot.), a low, soft grass ( Anthoxanthum odoratum), producing in the spring narrow spikelike panicles, and noted for the delicious fragrance which it gives to new-mown hay; -- also called sweet vernal grass. See Illust. in Appendix.

   Vernal signs (Astron.), the signs, Aries, Taurus, and Gemini, in which the sun appears between the vernal equinox and summer solstice.