Common meaning:

A discipline that examines the consequences of being disabled.

Hidden meaning of the Equity religion: 

A discipline that considers a disability as something that is unjustly done to people and not caused by unfortunate circumstances.

Discussion:

Disability studies is a discipline where Equity believers try to figure out how the dominant group of healthy people has oppressed the minoritized group of the disabled.

Equity always assumes that every problem in life is caused by some oppressor group. This gets insane when disciples of the Equity faith study the cause of disabilities. Instead of identifying physical limitations and trying to figure out how to overcome them, the discipline spends almost its entire time trying to figure out how the oppression by healthy people has caused the problem. 

The Equity believers explain that the able-bodied people believe the cause of a disability is sickness or a physical limitation, when in reality, it is their oppression of the marginalized that is causing the issue. Deafness is only a problem because hearing people have labeled it as one and failed to accommodate their practices to include deaf people.

News flash:  physical limitations are actually real things and pretending they are not is just stupid.