If there is a chance of something happening, it is possible that it will happen.

If you have a chance to do something, you have the opportunity to do it.

A chance meeting or event is one that is not planned or expected.

If you chance to do something or chance on something, you do it or find it although you had not planned or tried to.

If you chance something, you do it even though there is a risk that you may not succeed or that something bad may happen.

Something that happens by chance was not planned by anyone.

You can use by any chance when you are asking questions in order to find out whether something that you think might be true is actually true.

If you say that someone stands a chance of achieving something, you mean that they are likely to achieve it. If you say that someone doesn't stand a chance of achieving something, you mean that they cannot possibly achieve it.

When you take a chance, you try to do something although there is a large risk of danger or failure.