This is the 17567th most frequent Russian word.
тротуарной
"Тротуарной" means "relating to a sidewalk" in English.
The word 'тротуарной' is used as an adjective to describe 'дорожки' (path), indicating that the path is part of or adjacent to a sidewalk.
Она шла вдоль тротуарной дорожки.
She was walking along the sidewalk path.
Here, 'тротуарной' modifies 'плитки' (tiles), specifying that the tiles are associated with the sidewalk.
Нам нужно провести ремонт тротуарной плитки.
We need to repair the sidewalk tiles.
In this example, 'тротуарной' describes 'зоны' (zone), pointing out that the area in question belongs to or is intended to be a sidewalk.