Thedis is of Greek origin, derived from the name 'Thetis', which means 'divine'. It is a unisex name, though more commonly used for females. In Greek mythology, Thetis was a sea nymph who gave birth to Achilles, one of the greatest heroes in Homer's Iliad.
"TheDis is quite rare, with only a few babies named thus each year between 1918 and 1925, totaling sixteen over those years."