noun
thin padded mat laid on tatami
A thin cushion or mat placed on top of tatami flooring for added comfort or protection.
祖母は座布団の代わりに上筵を使っていた。
My grandmother used a thin padded mat instead of a zabuton cushion.
Compound of 上 (うわ, 'upper') and 筵 (むしろ, 'woven straw mat'). The exact historical derivation is uncertain, but the word describes a thin mat placed on top of tatami.