Definitions of disability vary quite a bit from plan to plan. Most standard short-term disability and individually purchased disability policies require only that the claimant demonstrate that their injury/condition render them unable to perform the duties of their “own occupation.”
For example, suppose that you are a dentist and you severely injure your neck. Though you might be perfectly capable of performing a different job — assuming your disability coverage is based on an “own occupation” definition of disability — you would likely be entitled to receive disability benefits.
Most long-term disability plans provide for 24-months of benefits, after expiration of the elimination period, under an “own-occupation” definition of disability and then requires that you be disabled from “any occupation” in order to be eligible for benefits.
Some stricter plans only have an “any occupation” definition of disability. If your plan is based on an any-occupation definition of disability, you cannot secure benefits unless you demonstrate that you are unable to perform any alternative job (that you would otherwise be qualified for given your age, training, experience, etc.).