Strong's Definition
from 7665; the orifice of the womb (from which the fetus breaks forth)
KJV Usage: birth, breaking forth
STEPBible — Tyndale Abridged Hebrew Lexicon
מַשְׁבֵּר (mish.ber) — birth. 1) place of breaking forth, place of breach, opening 1a) of womb
UBS Dictionary of Biblical Hebrew
UBS Dictionary of Biblical Hebrew © United Bible Societies, licensed CC BY-SA 4.0.
Brown-Driver-Briggs Hebrew Lexicon
מַשְׁבֵּר n.[m.] place of breach, i.e. mouth of womb base