What does caching or not-Caching mean when talking about URL parameters (Matrix, Request or Path)

Question

I read in several posts as I'm learning about http requests about the term "Caching" I know it means faster access but how and where ?

1. Matrix Params are cached, Pattern: http://some.where/thing;paramA=1;paramB=6542
2. Request/Query Params aren't cached, Pattern: http://some.where/thing?paramA=1&paramB=6542
3. Path Params are cached, Pattern: http://www.rest.services.com/item/b

So what does caching mean in this scope? I googled but no luck.

And Are there any other URL patterns ?

Ref: 1,2 From here and 3 from here

Answer 1

All of these can be cached.

You may want to read

http://www.mnot.net/cache_docs/