All 5 Uses

Social Security
in
Into the Wild
(Auto-generated)

Curiously, when McCandless applied for the McDonald's job, he presented himself as Chris McCandless, not as Alex, and gave his employers his real Social Security number.†
p. 40.1 *
I think I've even got his Social Security number around here somewhere.'†
p. 100.9
Social Security number: "I forget."†
p. 101.1
And in the blank for Social Security number he'd put down, "228-31-6704.†
p. 101.2
The Social Security number turned out to be genuine and placed McCandless's permanent residence in northern Virginia.†
p. 101.2

Definitions:

(1) (Social Security as in: the US program)
generally thought of as the U.S. retirement income that is funded through payroll taxes (though social security legislation includes many other programs that provide a safety net for Americans)

In addition to retirement benefits, Social Security offers unemployment insurance, and assistance for dependents and the blind (now disability in general). In 1965, medical benefits were added through Medicare legislation and in 2003, prescription drug benefits were added.
(2) (meaning too rare to warrant focus)