This is the 11997th most frequent Polish word.
latek
The Polish word "latek" refers to a "year-old" (used to indicate the age of someone, typically after a numeral).
The term 'dziesięciolatek' here is a compound word indicating the specific age of 'ten years old.' It is used as a noun referring to a child of that age.
Janek to mój dziesięciolatek, który uwielbia grać w piłkę.
Janek is my ten-year-old who loves playing soccer.
The word 'latek' in this sentence is utilized in a colloquial genitive form to denote 'years,' emphasizing the passage of time.
Oglądaliśmy zdjęcia sprzed kilku latek, kiedy to rodzina była na wakacjach.
We were looking at photos from several years ago, when the family was on vacation.
Here, 'pięciolatek' signifies a 'five-year-old,' typically used referring to a child of that specified age in a descriptive manner.