The period from the end of World War II through the mid-1960s marked by unusually high birth rates.
a demographic phase marked by an increase in the birth rate of a conuntry, and a corresponding population increase
'Baby Boom' is the term applied to the period of time from January 1, 1946 to December 31, 1964 when there was a boom in the birth rate. This period of time saw over 77 million births occur.
Markedly higher birth rate in the years following World War II; led to the biggest demographic “bubble'' in American history.