The MERV on filters stands for and means Minimum Efficiency Reporting Value which was developed by the American Society of Heating, Refrigeration and Air Conditioner Engineers - ASHRAE.
The MERV or Minimum Efficiency Reporting Value is a rating given to the filters to show their efficiency at how well they work to filter the air.
The higher the MERV value on the filter the more efficient the filter is at filtering the air.
So when you buy and install a MERV filter for your heating and air conditioning then you want to get the MERV filter with the highest MERV value.
The higher the MERV rating number the better the quality and the better the filtering it will be able to do.