From badal; alloy (because removed by smelting); by analogy, tin -- + plummet, tin.
see HEBREW badal
H913. bedil
בְּדִיל noun [masculine] alloy, tin, dross (originally that which is separated from precious metal; compare PlinHist. Nat. xxiv. 16, xxxiii. 9) — ׳בּ absolute Numbers 31:22 4t.; Plural suffix בְּדִילָ֑יִךְ Isaiah 1:25; —
1 alloy, Isaiah 1:25 figurative of evil of Jerusalem, which ׳י will remove (הֵסִיר; "" סִגָ֑יִךְ).
2 tin (plumbum album) Numbers 31:22 (P; + עֹפָ֑רֶת בַּרְזֶל, נְחשֶׁת, כֶּסֶף, זָהָב,); figurative of Israel Ezekiel 22:18 (+ עוֺפֶרֶת בַּרְזֶל, נְחשֶׁת,); in simile 22:20 (+ id. + כֶּסֶף); as article of commerce brought to Tyre from Tarshish 27:12 (+ עוֺפֶרֶת בַּרְזֶל, כֶּסֶף,).
3 plummet, הַבְּדִיל הָאֶבֶן (appositive) Zechariah 4:10.