Roman God of War
Martial as in martial arts dates back the medieval latin word ‘martialis’ meaning ‘of Mars or war.’ Mars, of course is the Roman god of war.
Coxswain or Cox in Rowing
The word ‘coxswain’ comes from the early 14th century. He was the ‘officer in charge of a ship’s boat and its crew,’ from cock ‘ship’s boat’ + swain ‘boy’, from Old Norse sveinn ‘boy, servant’.
Down to the wire
The expression ‘Down to the wire’ came from horse racing and is used in a close finish. Horse races would have a length of wire stretched across a racetrack at the finish line to help determine the winner.