Aethusa (Gr. Αίθουσα) was in Greek mythology a daughter of Poseidon and Alcyone, who was beloved by Apollo, and bore to him Eleuther.[1][2][3]
The word aethusa was used as an epithet for a portico that was open to the sun, that is, Apollo.[4]
This article incorporates text from the public domain Dictionary of Greek and Roman Biography and Mythology by William Smith (1870).