From an unused root meaning to bestrew; ashes -- ashes.
H665. epher
אֵ֫פֶר noun [masculine] ashes (as light, flying?) — ׳א absolute Genesis 18:27 +; construct Numbers 19:9-10, — ashes of red heifer, used in purifications 19:9-10, on head, as sign of humiliation 2 Samuel 13:19; contrition Daniel 9:3 ("" שַׂק צוֺם,), Jonah 3:6 ("" שַׂק) compare Job 42:6 (וא ׳עָפָר), Isaiah 58:5 ("" שַׂק); mourning Esther 4:1, 3("" שַׂק) compare Job 2:8 (הא בתוך ׳ישׁב), Jeremiah 6:26 ("" שַׂק), Ezekiel 27:30 ("" עפר); in simile scattereth hoarfrost ׳כָּא Psalm 147:16; but also as filthy, loathsome וא ׳כעפר Job 30:19 (Di simile of mourning, grief), as worthless, א ׳מִשְׁלֵי 13:12 proverbs of ashes; figurative of worthlessness Isaiah 44:20; insignificance וא ׳עפר Genesis 18:27; ignominy Ezekiel 28:18; Malachi 3:21; distress & sorrow ׳א אָכָ֑לְתִּי כַּלָּחֶם Psalm 102:10 (so Assyrian compare ZimBP 42) compare Lamentations 3:16; Isaiah 61:3 (אֵפֶר תַּחַת מְּאֵר).
II. אפר (enclose, envelope, Assyrian apâru, attire DlPr 54; Thes compare Arabic , cover; MV compare Aramaic , מעפרא, mantle, turban; but connection of √ ()׳מּ ע with אפר is dubious)