Social Security disability is the federal program that provides monthly benefits and health insurance for disabled workers. This program is important enough that a full 15 percent of income earned in this country goes to support it through the means of the FICA payroll tax and matching employer contributions. Because Social Security only provides help for those who are completely disabled, it becomes incumbent that applicants understand the definition of "disabled" as espoused for this purpose.
There is no partial disability when it comes to collecting under the Social Security system. You're either completely disabled or you're not. To determine whether or not a disabling condition exists, a medical condition must be present that is expected to last at least a year or result in death. This is a pretty severe test, and the possibility certainly exists that a person could have a serious condition yet still be able to perform "substantial work" in the eyes of the Social Security determining board.
For the purposes of determining full disability, Social Security breaks work down into four different types -- sedentary, light, medium and heavy -- and then goes on to define the kind of physical demands and motions associated with each. For example, sedentary work requires a person be able to lift up to 10 lbs., stand or walk up to two hours daily, and sit up to six hours daily. A person under 55 years of age would normally have to medically prove he cannot do sedentary work to receive full disability benefits.
Social Security does recognize that even a fully disabled individual can't be expected to sit in a chair all day and stare at the television. Toward that end, recipients are allowed to earn money up to a certain level and still receive their monthly check. At some point, usually around $1,000 in monthly earnings, benefits will begin to be taken away for months during which substantial work was performed. Perform substantial work long enough and you will likely no longer be classified as fully disabled.
Social Security disability isn't the only game in town when it comes to claiming full disability. Many private insurance plans through employers offer disability insurance. The definition of "fully disabled" is likely to differ slightly from plan to plan, and those interested in more information should contact the plan administrator where they work. In general, though, the definition of full disability means that you meet the criteria to collect the maximum amount of monthly benefits due to being unable to perform any kind of work.