Meanings
Usage patterns
胴を鍛えるto strengthen one's torso/core
I'm strengthening my core with sit-ups.
胴を打つto strike the plastron (score a dō hit in kendo)
He landed a beautiful strike on his opponent's plastron.
胴が決まるfor a dō strike to be scored as a valid point
The referee's call confirmed the dō strike as a valid point.
Expressions
胴が長いlong-bodied; having a long torso