As a Noun: 1. The thing that makes an event happen. English = cause. 2. The fact or situation which explains why something happens or exists. English = reason. As Modifier: 1. Used to link or join two sentences of which the second is the reason or cause of the event or events described in the first. English = because. 2. Used to introduce the reason, cause or explanation of something. English = because, since, as. As Question: 1. Used alone or at the beginning, end, or at both the beginning and end, of a sentence to ask about the reason or cause of something. English = why. 2. Often used with WHAT to ask for the reason you have been asked or ordered to do something when you are reluctant to do it. English = 'What's the reason?', 'What for?'