Meaning of FOK

This is an acronym of Fill-Or-Kill. This is used by traders intending to buy huge amount of a token/coin and does not want just part of the total order filled but want all filled or order should not be executed at all if it will only be partial filling.

For example a trader needed 50,000 units of a token and not ready to execute the trade even if it could fill upto 45,000+, it just has to be the 50,000 or none at all.