Where does “Thalia” come from?

Thalia is the English form of Ancient Greek Θαλία, a name of uncertain original meaning.

Ancestry of “Thalia”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Θαλία	—
2	Ancient Greek	θάλλω	to bloom, sprout; to grow, flourish, thrive; to...
3	Proto-Indo-European	dʰelh₁-	blossom; be green; to bloom, be green

Thalia — Etymology, Origin & Word History | Etymology Explorer