At a very elementary level.
Consider an example -
You run a company and you have to pay to 100 of your employees .
It would be better if you work more for the development of your company,
Rather than preparing 100 cheques or cash or BTC worth that much to be given.
Also there is always a scope of mistake.
So escrow agents are the people hired to do this work.
And a payment given by escrow agent is called escrow payment.