From an unused root meaning perhaps to arch; a couch (properly, with a canopy) -- bed(-stead), couch.
H6210. eres
עֶ֫רֶשׂ noun feminineJob 7:13 couch, divan; — construct ׳ע Deuteronomy 3:11 +; absolute עָ֑רֶשׂ Amos 3:12; suffix עַרְשִׂי Job 7:13 +, etc.; plural suffix עַרְשׂוֺתָם Amos 6:4; — couch, divan, 3:12; 6:4 ("" מִטּוֺת), + 2 Samuel 17:28 (read מִשְׁכָּב עַרְשׂת Klo NeMarg. 18 HPS, compare ᵐ5); for lying at night Job 7:13; Psalm 6:7 ("" מִטָּה), Proverbs 7:16, יְצוּעָ֑י עֶרֶשׂ Psalm 132:3 the coach of (consisting in) my bed; couch of sickness 41:4; marriage couch Song of Solomon 1:16; perhaps transferred to sarcophagus, as last couch בַּרְזֶל עֶרֶשׂ עַרְשׂוֺ Deuteronomy 3:11 (see Dr).
ערשׁ (√ of following; meaning unknown).