This is the 14623rd most frequent Turkish word.
plajdaki
"Plajdaki" means "at the beach" in English.
In this sentence, the word 'plajdaki' acts as an adjective denoting the location of the sands, specifying that they are 'on the beach'.
Plajdaki kumlar ayakkabılarımın içine dolmuş.
The sands on the beach have gotten into my shoes.
Here, 'plajdaki' qualifies 'insanlar', indicating that the people being referred to are those 'on the beach'.
Plajdaki insanlar denize giriyor.
The people on the beach are swimming in the sea.
In this sentence, 'plajdaki' modifies 'tatil', specifying the vacation that occurred 'on the beach'.