This is the 16th most frequent Persian word.
های
The Persian word "های" is a plural marker meaning "s."
In this sentence, the word 'های' makes the noun 'عکس' plural, so it means 'photos' instead of 'photo'.
دوستانم عکسهای مسافرتشان را نشان دادند.
My friends showed me the photos from their trip.
Here, 'های' again serves as a plural marker for the noun 'خانه', turning it into 'houses' from 'house'.
خانههای بزرگی در این منطقه است.
There are big houses in this area.
The word 'های' is being used as a plural marker for the noun 'کتاب'. It means 'books' instead of 'book'.