lumbar
From Longman Dictionary of Contemporary EnglishRelated topics: Human, Medicinelumbarlum‧bar /ˈlʌmbə $ -ər/ adjective technical HBHMrelating to the lower part of the back pain in the lumbar regionExamples from the Corpuslumbar• He was in that terrible state of lumbar pain where mobility involves a slow ambulatory squat.• The seats have built-in lumbar supports.Origin lumbar (1600-1700) Modern Latin lumbaris, from Latin lumbus “lower back”