counter
tatami mat counter; counter for tatami mats
Used as a counter for tatami mats, especially when expressing room size. One 畳 is typically about 1.82 sqm (in real estate) or 1.54 sqm (in other contexts).
この部屋は六畳です。
This room is six tatami mats in size.
八畳の和室を探しています。
I'm looking for an eight-tatami-mat Japanese-style room.
Also a counter for tatami mats, but more commonly used in real estate listings. 畳 is the more general and traditional counter.
From the noun 畳 (たたみ, 'tatami mat'), used as a counter. The reading じょう is the on'yomi of the kanji.