From an unused root meaning to divide; a cleaver, i.e. Iron armature (of a chariot) -- torch.
Englishman's Concordance
1) iron, steel Part of Speech: noun feminine A Related Word by BDB/Strong’s Number: from an unused root meaning to divide Same Word by TWOT Number: 1771
Brown-Driver-Briggs
[מְּלָדָה] noun feminine usually iron, steel (origin dubious; steel in Arabic is , but Vulgar Arabic ; Syriac (in Lexicons); loan-word from Persian according to LagGes. Abh. 75, compare NöZMG xxx(1876), 769, but uncertain, compare Now and references); — plural [absolute!] בְּאֵשׁמְּֿלָדֹתהָרֶכֶבNahum 2:4 < ׳כָּאֵשׁ מִּלְדֹת וגו We Now, like fire the steel (fittings) of the chariots.
Nahum 2:3 HEB:מְתֻלָּעִ֔ים בְּאֵשׁ־ פְּלָד֥וֹת הָרֶ֖כֶב בְּי֣וֹם NAS: are [enveloped] in flashing steel When KJV: [shall be] with flaming torches in the day INT: are dressed flashing steel the chariots When