ive been hearing more and more words on this site for pokemon they seem like classification.
i already know what UBER is but what are the others like tank and sweeper and those types of pokemon.
Those are called "Roles"
- Baton Passers
Here is a great description of them by Linkpower22 :D http://pokemondb.net/pokebase/38940/what-are-the-different-kinds-pokemon-competitive-battling#a38954
This link from Psypokes will help you understand more about tanks,sweepers,spinner,etc. in detail. Hope this helped :)
EDIT : Note that this is from Generation 3,but it applies to POKeMON from other Generations as well.