tatami

noun, plural ta·ta·mi, ta·ta·mis.

1. (in Japanese houses) any of a number of thick, woven straw mats of uniform dimensions, about three feet by six feet (91 cm by 183 cm), the placing of which determines the dimensions of an interior.

noun plural -mi or -mis

1. a thick rectangular mat of woven straw, used as a standard to measure a Japanese room

1610s, from Japanese tatami.