If someone is allowed to do something, it is all right for them to do it and they will not get into trouble.

If you are allowed something, you are given permission to have it or are given it.

If you allow something to happen, you do not prevent it.

If one thing allows another thing to happen, the first thing creates the opportunity for the second thing to happen.

If you allow a particular length of time or a particular amount of something for a particular purpose, you include it in your planning.

If you allow that something is true, you admit or agree that it is true.

Some people say 'Allow me' as a polite way of offering to do something for someone.

Some people use Allow me to... as a way of introducing something that they want to say or do.