Originally, a thing placed under the base of the head to sleep upon, hence a cushion, a seat or place to rest something upon. Cognate to Hebrew יְסוֹד (yǝsṓḏ, “base, foundation”), Aramaic אִיסָדָא (ʾĕsāḏā, “thing placed beneath, at the base or bottom; pillow”), Classical Syriac ܒܣܕܝܐ (bessāḏyā, “pillow, couch, place to rest upon”, literally “at the base or pillow”), Ugaritic 𐎊𐎒𐎄 (ysd, “base, foundation”), Akkadian 𒅖𒁲 (/⁠išdu⁠/, “base, foundation”), ultimately Proto-Semitic in origin.