Marketing qualified lead is a prospect that has come through expressing interest in one’s product and then converting into a lead. This lead fits the qualifications, or standards, that a lead must possess as determined by marketing.
Qualifications can be anything that fits with someone who will be most likely to buy the product or service.
For example a marketing qualified lead, with the qualifications that marketing sets, may have to fit within certain revenue numbers, the company that the lead is coming from may have to have a certain number of employees, or they have to come from a certain vertical.
The MQL is usually a lead that has progressed farther down the marketing funnel.