The Collaborative International Dictionary
packwax
Paxwax \Pax"wax`\, n. [For faxvax, fr. AS. fea? hair (akin to OHG. fahs) + weaxan to grow. See Wax to grow, and cf. Faxed, Pectinate.] (Anat.) The strong ligament of the back of the neck in quadrupeds. It connects the back of the skull with dorsal spines of the cervical vertebr[ae], and helps to support the head. Called also paxywaxy and packwax.
Wiktionary
packwax
n. (alternative form of paxwax English)