thecodont
Concise Oxford English Dictionary © 2008 Oxford University Press:
thecodont /ˈθiːkə(ʊ)dɒnt/
▶noun Palaeontology a Triassic fossil reptile of a group ancestral to dinosaurs and other archosaurs.
– origin C19: from mod. L. Thecodontia, from Gk thēkē ‘case’ + odous, odont- ‘tooth’ (because the teeth were fixed in sockets in the jaw).
'thecodont' also found in these Oxford entries:

