Lumbar refers to the lower part of the spine, specifically between the thoracic vertebrae (the upper back) and the sacral vertebrae (the bottom of the spine). It is also used as an adjective to describe something related to or affecting this area.
You are able to adjust the 8 way power driver seat with power adjustable lumbar support, to your comfort. (edmunds.com)
The vehicle tested came with adjustable lumbar support for both front seats. (motoring.com.au)
The 10 - way power adjustable seat for the driver with height adjuster and two - way power lumbar support provided adequate support, and the car is all - day comfortable. (hybridcars.com)