This is the 33rd most frequent Russian word.
лет
The Russian word **"лет"** means "years" (genitive plural form of "год").
In this sentence, "лет" is used to express a person's age in years.
Мне двадцать лет.
I am twenty years old.
Here, "лет" indicates a duration of ten years in the past.
Прошло десять лет с тех пор, как мы встретились.
It has been ten years since we met.
In this sentence, "летом" is a form of "лето" (summer), showing a time of year.