A boomer is someone who was born during the two decades after World War II. Boomers are part of an unusually large generation.
The term boomer is shorthand for baby boomer, the official name for a generation usually defined as spanning 1946 to 1964. These days, some younger people think of boomers as old and out of touch. Advertisers, however, are eager to win their attention because, on average, they have money to spend — and because there are so many of them. The "boom" part of the word comes from the sharp spike in U.S. birth rates after World War II ended.