In anatomy, the loin; the lumbar region of the body.(noun)
The Century Dictionary (Public Domain)
Use "lumbus" in a sentence
"If NBC's Co-lumbus, Ohio, affiliate passes from Outlet Communications to the network itself-another of last week's deals-fans of "Frasier" will be hard pressed to tell."
"The citizens of Co-lumbus, New Mexico, would, in 1916, have found that surprising."
"Etymology: Middle English loyne, from Middle French loigne, from (assumed) Vulgar Latin lumbea, from Latin lumbus; akin to Old English lendenu loins, Old Church Slavonic ledvije"