Theano was a 6th century Greek philosopher, who has been called both the wife and student of Pythagoras, though not enough is known about her life to say which was true. Her surviving writings focus on how to deal with children, physicians, philosophers, servants, and unfaithful husbands. 
 
Also held by several minor figures in Greek mythology, the name derives from the Greek thea meaning "goddess". Theano is currently a very obscure choice in the US, however, the short form Thea might make it feel familiar to those outside of Greece. 
 
Politician and architect Theono Fotiou is one notable bearer while Theano is also the name of a software for evaluating mathematical expressions.

Theano

Theano Origin and Meaning