Definition of "abelisaur"

Juvenile T. rexes were light and agile before they leveled up into the adults we’re more familiar with. […] Other megatheropods, including abelisaurs and tarbosaurs, also grew from turkey-like hatchlings to bus-sized behemoths over the course of their lives.

2021 February 25, Cara Giaimo, “The Outsized Influence of Teen T. Rex and Other Young Dinosaurs”, in The New York Times‎