Blockchain is the underlying technology of cryptocurrency, although not just used for financial transactions. The primary purpose is to keep a record of all the information that has gone through the network in a way that is impossible to change, cheat or hack - this is called a ledger...
A Blockchain consists of many “blocks” which hold information (i.e transactions), TENT for example generates a new block every 1 minute and all blocks can be checked past and present, this can’t be changed because it is hard coded into the network design.
A blockchain network consists of many computers running 24,7 with a full copy of the Blockchain stored from the first block to the current one. Every computer or “Node” as they are known are fully synchronised between each other, so any transactions which are made on the network are verified by the whole network. Any transactions that are not verified by the whole network are rejected and are not authorised.