Second Conditional: unreal possibility or dream
The second conditional is like the first conditional. We are still thinking about the future. We are thinking about a particular condition in the future, and the result of this condition. But there is not a real possibility that this condition will happen. For example, you do not have a lottery ticket. Is it possible to win? No! No lottery ticket, no win! But maybe you will buy a lottery ticket in the future. So you can think about winning in the future, like a dream. It's not very real, but it's still possible.
Notice that we are thinking about a future condition. We use the past simple tense to talk about the future condition. We use WOULD + base verb to talk about the future result. The important thing about the second conditional is that there is an unreal possibility that the condition will happen.
Here are some more examples:
Sometimes, we use should, could or might instead of would, for example: If I won a million dollars, I could stop working.