They're just words describing when a certain generation was born.
"Boomer" means people born during the baby boom post WWII. Born from aprox. 1946-1965 Gen X are the ones born from aprox. 1965-1980. The people that were generally teens when MTV was a cultural juggernaut. Gen Y or Millennials are most of the people here. Those that experienced their teenage years around the turn of the millennium Gen Z are the ones born around the turn of the millennium to about the early 2010s.