Кресло с подлокотниками. Стул без подлокотников. Толковый словарь по ссылке: http://slovarozhegova.ru/

стул = chair кресло = armchair Here is the tip. Type each word in Google, then switch to Google Images and by looking at the images that Google finds you'll understand the difference.

Кресло is bigger and softer. In English it's an armchair. Стул is a chair.