The area on either side of a road.
"The farmer parked his truck on the roadside to unload fresh produce from his fields."
In plain English: Roadside is the area right next to where cars drive on a road.
"The driver stopped at the roadside to tie his shoe."
Located beside a road.
"The old oak tree stood roadside, casting long shadows over the passing cars."
The word roadside is a straightforward combination of the words "road" and "side." It literally means the area located next to or alongside a roadway.