Definition of "astral"

Some Aſtral forms I muſt invoke by prayer, / Fram'd of all pureſt Atoms of the Air; [...]

1669 June (first performance), John Dryden, Tyrannick Love, or, The Royal Martyr. […], London: […] H[enry] Herringman, […], published 1670, Act IV, scene i, page 29

Now both of you sit there and wait for any guides to come to you, any astrals or people from that life to make themselves known to you.

2009, David Wells, David Wells's Psychic Secrets, page 112