in the post

1. In the process of being sent or delivered by the public mail system. Primarily heard in UK. I hope my mother's letter hasn't gotten lost in the post! They said that my work permit is in the post. I hope it arrives soon! Every time I order something from that company, it ends up lost in the post!

2. In a letterbox or other point of collection for delivery by the public mail system. Primarily heard in UK. I put your cheque in the post yesterday, so it should reach you the end of the week. I need to get her birthday card in the post today or else it will be late. The package is already in the post? Oh good, then it should be arriving soon.