millennial in Czech

Thousand-year-old; also (by extension, loosely) thousands of years old.

(originally, US, demography) Often capitalized: a person from the generation born in the last two decades of the 20th century, from around the early 1980s to the mid-1990s and who reached adulthood early in the third millennium C.E., characterized by their familiarity with computer technology and poorer financial prospects than their parents.