From an unused root meaning to envelop; a wrapper, i.e. Shirt -- fine linen, sheet.
H5466. sadin
סָדִין noun [masculine] linen wrapper (perhaps foreign word; compare Assyrian sudinnu DlHWB 490, a garment; Late Hebrew סְדִינָא ᵑ7 סָדִין,, Syriac , (rare) Mark 15:46; > compare Arabic , veil, saddle-cover (see Lane1335), or , Greek [and ᵐ5] σινδών, compare Frä48 LewyFremdw. 85); — absolute ׳ס Proverbs 31:24; plural סְדִינִים Judges 14:12; 14:13; Isaiah 3:28; — wrapper or rectangular piece of fine linen, worn as outer, or (at night) as sole garment (compare GFMJudg 14, 12), + בְּגָדִים חֲלִמֹּת 14:12-13, in list of women's finery Isaiah 3:23, made and sold by the capable woman Proverbs 31:24.
סדר (√ of following; compare Assyrian sadâru, arrange in order, sidru, sidirtu, row, battle-line; Late Hebrew סָדַר arrange, order, Aramaic סְדַר, , all with derivatives ).