aitch·bone 
(
āch
b
ōn
′)
n.1. The rump bone, especially of cattle.
2. The cut of beef containing the rump bone.
[Alteration (influenced by AITCH) of Middle English hach-boon, from an hach-boon, an aitchbone, alteration of a nachebon : nache, buttock (from Old French, from Late Latin naticās, accusative pl. of natica, buttock, from Latin natis) + bon, bone; see BONE.]