From an unused root meaning to burst forth; a fountain -- spring.
H5033. nebek
[נֵ֫בֶךְ] noun [masculine] spring (si vera lectio) (v unknown); — only plural construct נִבְכֵייָֿם Job 38:16 the springs, sources of the ocean ("" תְּהוֺם חֵ֫קֶר); — Ol Siegf נִבְלֵי; Bu suggests נבעי = מֵבֻּעֵי as possibly; but Gr Perles read נִבְכֵי 28:11, also, for Masora מִבְּכִי, compare נָהָר 2
I. נבל (√ of following; meaning dubious).