Teacheress is a synonym of educatress.
As nouns the difference between teacheress and educatress
is that teacheress
is (archaic) a female teacher while educatress
is (dated) a female educator.
(archaic) A female teacher.
* Although once recommended by no less an authority than Fowler, use of this word is deprecated by most modern writers. It has survived somewhat longer in Indian English.
(dated) A female educator.