This is the 207th most frequent Hebrew word.
אלפי
"אלפי" means "my thousands" or "thousands of."
In this sentence, 'אלפי' is used as a quantifier, expressing 'thousands of' stars.
ישנם אלפי כוכבים בשמיים בלילות בהירים.
There are thousands of stars in the sky on clear nights.
Here, 'אלפי' serves the function of indicating 'thousands of' supporters.
הוא זוכה לתמיכה מאלפי אוהדים במשחקים.
He receives support from thousands of fans during games.
'אלפי' in this sentence again acts as a quantifier, qualifying the word 'שקלים' (shekels) to mean 'thousands of shekels'.