Ruqun (襦裙) is a set of attire in hanfu which consists of a short jacket worn under a long skirt.
An aoqun is the opposite; hanfu where the top is worn over the skirt (not tucked in).
Ruqun is however a very broad term, an umbrella term for any kind of hanfu wherein the top is tucked into the skirt. Try to use one of the more specific terms below.