Tera is a decentralized application platform. This is akin to an operating system. Tera consists of a repository of programs and data storage integrated into the Internet. The mechanism for publishing programs and data on this platform is free from censorship. The circulatory system is the blockchain.
TOPCOIN is a type of crypto-currency, released February 2nd, 2014, with which you can make instant person to person payments, anywhere in the world. TOPCOIN also has a built in staking feature that allows you to collect more coins if you have some in your wallet!