### Question
How is the term retirement system defined?


### Answer
The term **retirement system** is defined in *42 U.S.C. § 410* as the following:

> given such term by section 418(b)(4) of this title;

#### Citation:
  - *42 U.S.C. § 410*
  - Heading: **CHAPTER 7-SOCIAL SECURITY > SUBCHAPTER II-FEDERAL OLD-AGE, SURVIVORS, AND DISABILITY INSURANCE BENEFITS**

