This is the 8703rd most frequent Russian word.
патрульная
Female patrol officer.
Here, 'патрульная' functions as an adjective derived from 'патруль' (patrol) and describes 'машина' (car).
Патрульная машина поехала вдоль улицы.
The patrol car drove along the street.
In this sentence, 'патрульная' is used as a nominalized adjective, referring to a female patrol officer explicitly.
Патрульная остановилась, чтобы поговорить с очевидцем.
The patrol officer stopped to talk to a witness.
Here, 'патрульная' serves as an adjective describing the 'группа' (group), denoting that this group is associated with patrolling duties.