Answer :
Frequently, you’ll hear people say that “retirement age” is 65. What are they referring to? People who say this are referring to the age in which you can receive your full Social Security retirement benefits. At different ages starting at age 62, you are eligible to receive a percentage of the benefits, once you hit 65, you can receive your full percentage/allotted amount.
Retirement age is 65, means in the Government Firms, the age limit to work for them is 65. After this age, employees will stay at home and enjoy their retired life. Employees' social security benefits will begin, pension, medical etc are given to them while staying at home.
Retirement age is different in different countries. Some countries have a retirement age of 65, some have 62 and some have 60.