Why do I need to know alors?
French speakers pepper conversation with alors all the time. It's one of those words that you can go by years without knowing exactly what it means, but will make you sound a lot more natural when you talk.
What does it mean?
Alors has several meanings.
It can be used to mean 'then' or 'in that case'. For example, Si tu sais conduire, alors tu peux prendre la voiture. (If you can drive, then you can take the car.)
Or it can mean 'so', 'well' and in informal conversation, 'so then'.
For example Alors, raconte ce qui s'est passé! (So, tell me what happened!/Well? Tell me what happened!)
Alors on its own is often used. When I ate in a café I often sighed and said Alors. There then was a sort word mexican wave with everyone saying Alors. Also Bon Alors is often used. I have tried Mal Alors but I am told this does not make sense.