From nahar; properly, a channel or fissure, i.e. (by implication) a cavern -- den.
see HEBREW nahar
H4492. minharah
[מִנְהָרָה] noun feminine dub., only plural בֶּהָרִים אֲשֶׁר הַמִּנְהָרוֺת Judges 6:2 (+ הַמְּעָרוֺת caves, הַמְּצָדוֺת strong-hold) — (clearly, si vera lectio, from a check נהר, but with what meaning? SchuJob 49 compare Arabic , [which means a place hollowed out by water], and rend. crevices, ravines, so Thes and others; Ra Ki WetzstHauran, 46 think of caves with a light-opening; R. Levi ben Gerson beacons, i.e. towers for fire-signals, GFM; but II. נהר late in Hebrew; ᵐ5 τρυμαλίας, ᵑ9 antra; Bu thinks הַמְּעָרוֺת a gloss explaining ׳הַמִּנ).