Market-not-held order vs Best efforts order

What is the difference between market-not-held order and Best efforts order? Both place discretion in the hands of the broker. Thank you.

IMO: Market not held order is a specific strategy adopted by the broker where he quotes a price (obviously not market price) and waits for any favorable quote to hit it. Its a relaxed strategy with no urgency to trade whereas in best effort order, the trader places a considerable faith / freedom to broker to do his best to get best price (specifics of the strategy is not discussed)

Anyone else has an answer to this?

Can I say best efforts order include both “market not held order” and “limit not held order”?