畳む
たたむ · tatamu · JLPT N3 · verb-godan
to fold (clothes)
👕 Same root as tatami: the mats were named for being folded and stacked
Tatami (畳) comes from tatamu, to fold or pile up. Early mats were thin and could be folded away when not in use, and the same kanji 畳 is used in both words. If you know tatami, you know tatamu: tata- = fold.