X Y Z

 X Y Z  The slang phrase XYZ, meaning “examine your zipper,” has been used since at least the 1960's 

These letters are used for constants (because “c” stands for “constant”). xyz - because they are the last three letters of the alphabet. These letters are used for variables and unknowns (because “x” is symbolic if the unknown - a mystery, as in “x marks the spot”, “Mister X”, etc.).

Generation X (1965-1980)

Generation X is the demographic group following the baby boomers. They are described as people born between 1965-1980.

As of 2019 U.S. Census data, there are 65.2 million Xers in the United States. Most of the members of this group are the children of the Silent Generation and early boomers. Meanwhile, they are often the guardians of Millennials and Generation Z

Millennials (1981-1996)

Millennials are also known as Generation Y and were born between 1981-1996.

Generation Z (1997-2012)

Generation Z is commonly known as Zoomers. They are the new generation after the Millennials and preceding Generation Alpha.

This generation was born in the mid-1990s and the early 2010s. The people from this era are children of Generation X. The effect of the economy has been known by this age group as being shaped by COVID-19.

And there you have the END of this ABC challenge.