This is the 26th most frequent Persian word.
هزار
"هزار" means "thousand" in English.
In this sentence, "هزار" is used as a cardinal number to quantify the noun "کتاب" (books).
من هزار کتاب خواندهام.
I have read a thousand books.
Here, "هزار" is used metaphorically to exaggerate the frequent repetition of an action, emphasizing annoyance.
هزار بار به تو گفتم که این کار را نکن.
I told you a thousand times not to do this.
In this case, "هزار" is used symbolically to underline the abundance or multitude of aspirations.