A block refers to a set of bitcoin transactions from a certain time period. Blocks are “stacked” on top of each other in such a way that one block depends on the previous. In this manner, a chain of blocks is created, and thus we come to the term “blockchain”.
Finding and publishing new blocks is what Bitcoin miners do to earn bitcoins. Whenever a new block is broadcast, approximately every 10 minutes, a quantity of bitcoins is received by the miner who solved that block. Bitcoin miners keep the network secure, and this is how they are rewarded. This system ensures that all transactions are valid, and keeps the bitcoin network secure from fraud.
If you’ve ever waited for a new bitcoin transaction to be confirmed, you were waiting for a new block to published containing your transaction. When that happens, the bitcoin network has deemed your transaction valid. CoinZoom currently requires 3 network confirmations before the transaction is considered finalized, however this number will vary with other Bitcoin services.