What is the definition?

From:  "Julia Jones"

What is lumbago?

TB sent us this to help out: 

This website should help you: here

amrshalakanidr gave his doctorate advice with this: 

in short it's back disc pain that extends to the legs due to compression of nerve roots. it usually affects the lumbar part of the spine and hence the word (LUMBago).

Mark and others responded with this definition: 

\Lum*ba"go\, n. [L., fr. lumbus loin. See Lumbar.] (Med.) A rheumatic pain in the loins and the small of the back.
Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
lumbago
n : backache affecting the lumbar region or lower back; can be caused by muscle strain or arthritis or vascular insufficiency or a ruptured intervertebral disc

Schwick simply stated this: 

Lumbago is soreness or stiffness of the lumbar area (lower back).

Curt rattled off this answer: 

A painful condition of the lower back, as one resulting from muscle strain or a slipped disk.

nick gb added this thought: 

Pain in the lower back, usually caused by muscle strain or a slipped disc. From the Greek lumba-, meaning pain. And the Turkish -go, indicating a focus in the lumbar region.

rOxY shared this website: 

heres a website

dragonjase summed it up with this: 

n : backache affecting the lumbar region or lower back; can be caused by muscle strain or arthritis or vascular insufficiency or a ruptured intervertebral disc