Hi Thanks for taking the time to comment on my blog. Wellies are Wellington Boots, you might know them as Rubber Boots perhaps. https://en.wikipedia.org/wiki/Wellington _boot
They are named after the Duke of Wellington. Wellie Socks are long socks that you wear in your wellies to keep your feet warm. They are long so they turn over the top of your boot and then don't slide down your leg when you are wearing them.
Hope that helps I don't actually know anyone in the UK who doesn't have a pair of Wellies. 123 days ago