Lumbar lordosis refers to the natural curve in the lower part of your back, known as the lumbar spine. It is a normal inward curve that helps to support your body and balance your posture. Full definition
It is typically seen in the lumbar spine (lower back), and usually accompanied by straightening of the spine from the side view (loss of lumbar lordosis). (srs.org)
This compensation and overworking of the lower back is called excessive lumbar lordosis. (acefitness.org)
Lordosis is when the bones of the spine appear to be forward when seen from the side; this is most commonly seen in lumbar lordosis where the concave part of the low back has too much curve. (thoughtco.com)