Lumbago
/lʌmˈbeɪɡəʊ/
Definition 1 of 1
Pro Tip 1/3Medical Condition
Lumbago is a medical term; use it in health-related discussions. 
The doctor asked if I had a history of lumbago.
Pro Tip 2/3Specific Pain
Lumbago refers only to pain in the lower back, not elsewhere. 
My grandmother has lumbago, so she has trouble bending over.
Pro Tip 3/3Not Injury
Lumbago is not an injury but a symptom often caused by injuries. 
He has lumbago, but we don't yet know what's causing it.