Let's say it's about half-way through the morning, our 10:00 hrs.
Well, we all know that AM is short for ante meridiem i.e. Latin for "before noon". But did you know that the Romans said it literally, i.e. "10 AM" meant ten hours before noon, i.e. our 02:00 hrs?
Not content with that confusion, their descendants decided to start the day at sunset - so half-way through the morning back then, their stupid clock would show somewhere between 15 o'clock and 16 o'clock!
This one, with its markers in the middle of the hour, would show exactly 15 o'clock.
And then there's "noon" which comes from medieval Church time, and was originally our 3 PM!
The Church started it's day at dawn, prime being the first hour, and said prayers every three hours more or less. However, the monks weren't allowed to eat before none the ninth hour, so they reduced the intervals between prayers until "nones" were said just after midday. Hence, our "noon" comes from the ninth hour of the Church day.