Vocab- Mark of Athena

I have found a few unique words in Mark of Athena. One of them is ballistae, I predict that it is similar to a sail but it is older and has to be tied down for it to work. The textbook definition of ballistae is an ancient military engine used by Greeks. Another unique word is praetor, which I predicted meant a leader or a large group of people or warriors. The definition of this word is a chief elected to serve justice to serve under other leaders in Roman times.The final word is hippodrome, I think this word resembles an arena where people race horses.  The definition of hippodrome is a track or course that Romans and Greeks race chariots and horses for sport. I think I was accurate with this prediction of hippodrome because I knew they raced horses and I knew it had to be a track of some kind.