What are some similarities and differences between therapsids and thecodonts?

Therapsids started as a group of reptiles with an erect posture and feet that pointed forwards. Many also had incisors, canines, and molars. Mammals evolved from therapsids, and hence are considered to be a member of the therapsid group.

Thecodont was a term used to group certain archosaurian reptiles. However, it has been discovered that these reptiles did not belong to one group, hence the term "thecodont" is dubious. In any case, archosaurs are reptiles including dinosaurs, crocodilians, birds, and others.