This is the 117th most frequent Polish word.
tysięcy
"Thousands."
Here, 'tysięcy' is used in the genitive plural form to complement the number 'pięć', as required by Polish grammar rules.
Mam na koncie pięć tysięcy złotych.
I have five thousand zlotys in my account.
Here, 'tysięcy' matches the noun indicating thousands as a rough quantity (kilkanaście means several between 11 and 19).
Koszt budowy wyniósł kilkanaście tysięcy dolarów.
The cost of construction amounted to several thousand dollars.
In this instance, 'tysięcy' is also in the genitive plural form, applied after the word 'dziesięciu' to describe the quantity of 'ludzi' (people).