Tatami Mat, Tatami
noun
The kanji and the word are exactly the same. That means they share meanings as well.
たたみ
The reading comes right from the vocab meaning, which is tatami mat. The たたみ part, specifically.
私は畳の上に脱ぎ捨てられた、表裏が逆になった皺々のワイシャツを見つけました。
I found his inside out, wrinkled dress shirt on the tatami where he threw it.