An arm chair is a comfortable, cushioned chair with a support on each side, where you can rest your arms while you sit. Some arm chairs are big enough that you can curl up and read a book in them. Arm chairs are distinguished by their "arms," rests built to comfortably support your arms.
What is the difference between an arm chair and a side chair?
Traditionally, side chairs are the armless seats that are placed along the long sides of a rectangular table; arm chairs are reserved for the “heads” of the table.