From the same as meach; fat, i.e. Marrow -- marrow.
see HEBREW meach
H4221. moach
מֹחַ noun masculine marrow (Late Hebrew מוֺחַ, Arabic , Aramaic מוֺחָא, all marrow, brain); — only construct יְשֻׁקֶּה עַצְמוֺתָיו מֹחַ Job 21:24 figurative of prosperity.