A turbellarian flatworm of the order Rhabdocoela, characterized by a straight, unbranched gut.
In some modern classifications Rhabdocoela is ranked as a subclass.
Of, relating to, or characteristic of the order Rhabdocoela; (more widely, of the gut of a flatworm) straight and unbranched.
Mid 19th century; earliest use found in Proceedings of the Royal Society of London. From scientific Latin Rhabdocoela, order name from post-classical Latin rhabdo- + ancient Greek κοῖλος hollow (also as noun, κοῖλον, cavity of the body) + scientific Latin -a.