Of uncertain derivation; crimson, properly, the insect or its color, also stuff dyed with it -- crimson, scarlet (thread).
שָׁנִי42 noun [masculine] scarlet (properly coccus ilicis, which attaches itself to leaves and twigs of quercus coccifera; the dried body of female yields colouring matter; compare TristrNHB 319 PostHast. DB SCARLET M'LeanEncy. Bib. id.); — usually הַשּׁ ׳חוּט הַזֶּה שָׁ ׳תִּקְוַת Joshua 2:18 this cord of thread of scarlet, ׳ת ׳הַשּׁ 2:21, הַשּׁ ׳חוּט Song of Solomon 4:3 (simile of lips); so ׳(הַ)שּׁ alone Genesis 38:28, 30 (J), and as material of clothing 2 Samuel 1:24; Jeremiah 4:30; Proverbs 31:21 (plural שָׁנִים; on order of ll. see Toy); plural also in simile Isaiah 1:18 if your sins are like scarlet (robes); elsewhere (P) (הַ)שּׁ ׳תּוֺלַעַת (see ׳ת) of material for curtain, veil, ephod, etc., Exodus 25:4; 26:1 24t. Exodus; ת ׳בֶּגֶד ׳שׁ Numbers 4:3 (see II. ׳ב 2); construct (הַ)תּ ׳שְׁנִי used in purification, Leviticus 14:4, 6, 49, 51, 52; Numbers 19:6.