why do some verbs have the word "Se" in front of them in the infinitive form?

the pronown "se" is put in front of reflexive verbs. reflexive verbs are used for an action done to oneself, for example "laver" means to wash but "se laver" literally translates as "to wash oneself". the pronown changes as we talk about other people doing the action .Reflexive verbs follow the normal pattern and many are regular -ER verbs with just an extra pronown.eg. se laverje ME lavetu TE laveil SE lavenous NOUS lavonsvous VOUS lavezils SE lavent