It seems like everybody is mixing up things here.
Block Trade (re: links that xandman shared) has nothing to do with the order book.
There are trades that are done outside the exchange, usually with institutions, which meet a minimum volume. Once done, they need to be reported to the exchange, and usually (depending of the trading product type) they are identified in the market data feed with a special marker.
As for the term 'order block', I've never heard of it.
Block Trade (re: links that xandman shared) has nothing to do with the order book.
There are trades that are done outside the exchange, usually with institutions, which meet a minimum volume. Once done, they need to be reported to the exchange, and usually (depending of the trading product type) they are identified in the market data feed with a special marker.
As for the term 'order block', I've never heard of it.