moellon
/ˈmwɛlɒn/(also moëllon) Tanning
noun
A dark wax or grease used in curing leather; = degras.
Origin
Late 19th century. From French moellon, alteration (probably after moelle marrow and -on, diminutive suffix) of moleau from mou, mol soft + -eau. Perhaps compare earlier moelline.