This is the 3883rd most frequent Spanish word.
trasera
"Trasera" means "rear" or "back" in English.
In this sentence, 'trasera' is used as an adjective to describe the location of something ('parte'), indicating that it is at the rear or back.
El jardín está en la parte trasera de la casa.
The garden is at the rear part of the house.
Here, 'trasera' modifies 'puerta' as an adjective to specify that the door mentioned is the one at the back.
La puerta trasera estaba cerrada con llave.
The rear door was locked.
In this sentence, 'traseros' is the plural form of the adjective 'trasera,' describing 'asientos' to indicate they are located near the back.