As a Level One word, a post is a pole or large stick of wood, used to fasten or attach things to. In this picture, the horse is tied to a hitching post. The word is very old in English–it comes through Old French from Latin postis.
But post in Latin (not postis) also means (as a preposition) “after.” There are many Level Two words in English that derive from post with this meaning. Here are some:
To postdate a check means to write a bank check and put a date on it that is a little later than the day you write it. The postdated check only becomes valid for exchange on the date you write. Example: Do you mind if I postdate this check? I don’t have money enough to cover it right now, but I will get paid in three days and then you can take it to the bank.
Posterity means those who come after us: our children, our grandchildren, and all the rest of our descendants. Example: The paintings and sculptures preserved in the Art Museum are being safeguarded for posterity.
Postgraduate refers to studies taking place after graduation from college or university, i.e., studies for a master’s or PhD degree. I did my postgraduate work in China after I graduated in Germany.
Posthumous (pronounced PAHS tyu mus) is an adjective that refers to an event that occurs after someone’s death. For example, a posthumous child is a child that is born after the father’s death. A posthumous award is an award given to someone after his or her death.
To postpone simply means to put something to a later date in time–delay or put off. Professor, can I postpone my presentation? I can have it ready by Monday, but I’m not ready now.
Here is a great website with more words with the meaning of “post” as “after.”