Protoheterotrichida is an order of karyorelict ciliates.[3] It contains the family Geleiidae.[4][1]
The term Protoheterotrichida derives from the three ancient Greek words πρῶτος (prôtos), meaning "first, earliest, most prominent", ἕτερος (héteros), meaning "another, different", and θρίξ, τριχός (thríx, trikhós), meaning "hair",[5][6] in reference to the potential evolutionary affinities of these ciliates with the heterotrichs.[2]