<<Can someone please explain to me what the disease lordosis is?>>
Lordosis is not a disease - it is a "sign" as opposed to a "symptom". In
other words an observed change that may indicate an underlying disorder.
In this case lordosis refers to a curvature of the spine in the vertical
direction as opposed to scoliosis which is curvature in the side to side
direction. In my opinion the two terms are for practical purposes
interchangeable ( except for ageing - which tends to produce lordosis
rather than scoliosis)
Bruce Hansen
ANGFA