This is the 12289th most frequent Spanish word.
lavan
"Lavan" means "they wash."
In this sentence, 'lavan' is a verb conjugated in the third person plural present tense, indicating that the subject 'ellos' actively performs the action of washing.
Ellos lavan los platos después de cenar.
They wash the dishes after dinner.
Here, 'lavan' is part of a reflexive construction 'se lavan', showing the action of washing performed on oneself, referring to the hands.
Las manos se lavan antes de comer.
Hands are washed before eating.
In this usage, 'lavan' is in a passive construction where the subject (cars) receives the action indicated by the verb.