Here's a breakdown:
* Oars: Long, wooden or metal poles with blades used to propel a boat through water.
* Row: To propel a boat using oars.
* Oarsmen: The plural of "oarsman," which is a person who rows a boat.
So, "oarsmen" are the people who power a boat by rowing with oars. This term is often used in contexts related to rowing competitions, historical seafaring, or any activity involving rowing boats.