GI Side Cap

This is reproduction WW2 American GI side cap 

Apparently GI originally meant military equipment made from galvanised iron in WW1, but eventually became anything that was army general issue or government issue and on from that became a word to describe a soldier from the United States of America.

This cap sport 3 stars which means I'm a commander.

This style of hat in the US can also be known as a Campaign cap, flight cap, garrison hat, fore-and-aft cap, envelope cap, overseas cap. It also has some less polite names one being piss-cutter. 

Side Cap

A side cap is a fold-able military cap with straight sides, no brim and hollow crown which when worn forms a very distinctive shape.

In the UK its officially known as field service cap, in the US its called a garrison cap or flight cap.

The best feature of this cap is can easily be folded into a pocket, over the belt or under the shoulder strap of a military uniform. 

This cap sports a Russian badge so probably from a Russian unit but since I found it at cat boot I no idea for sure.

Tam O'shanter

A Tam O'Shanter is flat cap distinguished by woollen ball on top of the cap

The woollen ball, mini pom-pom is also called a Toorie and adorns many Scottish military or Highland dress.

Originally a Tam O'shanter would have been made of wool and would lie much flatter than this one.

A Tam O'shanter is basically a beret with a pom-pom on top.

The khaki cap here (or similar) was introduced in 1915 for wear in the trenches by Scottish infantry serving on the Western Front. This came to be known as the 'Tam o' Shanter' later abbreviated to 'ToS' by the army. 

Sham Scottish Hat

This is novelty Scottish hat, not quite the Tam O'shanter but sold as one.

Made with tartan fabric fixed to a black elasticated ring this hat allows you to play a caricature Scotsman.