Where did the slang term pooch meaning a dog come from?

The slang term "pooch" for a dog is thought to come from the German word "Pochen" which means "to thump" or "to beat".

This is likely a reference to the way dogs bark and wag their tails.

It's interesting to note that "pooch" as a slang term for dog has been around for a very long time, with records of it being used as far back as the 18th century.