Asa is a Sanskrit word and name, आशा (Āśā) it has different meanings but from the same central idea; hope, purpose, intention, wish... It can be spelled Āsā, Āsa, Asa, Asā, Āśā, Aśa, Āśa or Asha.
The name "Asa" is also used in Latin, meaning "the smallest" or "ace." The meanings are the same, as "ace" used to mean the smallest of things- think about how you put the cards 1, 2, 3, et cetera, on top of the ace card whilst playing Klondike/Solitaire.
It can be spelled Āsā, Āsa, Asa, Asā, Āśā, Aśa, Āśa or Asha.