It never starts with 666: Abbr.

• Payroll ID, for short
• Tax form ID (Abbr.)
• Box "d" on the IRS W-2
• ID with dashes
• Insurance form info: Abbr
• Application request: Abbr.
• Loan application fig
• Fig. on an application
• Fig. coveted by identity thieves

Wikipedia Word definitions in Wikipedia
SSN may refer to: