Al, If you are asking about fluid measure, technically a DRAM equals 0.125 fluid ounces (US) or 0.13 fluid ounces (UK). In Scotland, a dram used to be a pub measure of spirits equal to a quarter of a gill or 1.25 fluid ounces (4 gills = 1 imperial pint of 20 fluid ounces. A pint (US) is 16 fluid ounces). Later it was a fifth of a gill, or 1 fluid ounce. It is probably equal to a SHOT in the US of a fluid ounce (US) of liquor.
But, in layman's terms, "Not much!"
But "Cheers" anyway!