Weil means because in English. It is pronounced wEIl, as in it rhymes with file. It is a conjunction, but it does something really weird. It sends the verb, which is usually the second word in a sentence, to the end of the sentence. Here is an example:
Die Klasse ist toll, weil die Lehrerin sehr witzig ist.
(The class is awesome, because the teacher is very funny)
We're not used to this at all! In English, we say "because the car is old", but in German they would write "weil das Auto alt…