Retirement means when older people stop working and do other things that they like, without worrying about work anymore.
A long time ago, people didn't have retirement at all. If they were old or sick, they just had to keep working until they passed away or their families took care of them.
Around the late 19th and early 20th century, some workplaces started giving retirement benefits to their employees who have passed a certain age or worked for a certain number of years. This was mostly done for people who have physically demanding jobs, such as mining or factory work.
Later on, in 1935, the Social Security Act was passed in the United States. It provided retirement benefits to workers who have paid into the system throughout their working lives. This allowed older people to stop working and still have a source of income to rely on.
Over time, retirement has become more common and accepted in many countries around the world. Many governments have established retirement plans to support their citizens when they reach old age. Today, most people expect to retire when they get older, and enjoy their lives without having to work anymore.