The US dry pint is a unit of volume in the US customary system with the symbol dry pt.
1 US dry pint is equal to 1/8 of a dry gallon. This is equal to 1/2 US dry quart or 33.6003125 in³.
The dry pint was derived from the the British corn gallon which was 1/8 the standard 'Winchester' bushel or corn. This was the equivalent of 268.8 in³ when in dry form.
The barrel is a unit of volume used in the oil industry with the symbol bbl.
Oil is more commonly expressed in terms of cubic metres (m³) but in the US and in the economic world (mainly because such a large percentage of the world's oil is shipped to the US) as barrels.
The measurement of the barrel originated in the US at the first oil well in Pennsylvania. There were so many variants of barrel size (including those used for wine and other goods) that the distrust became so prevalent a central and standard barrel size was created. This was finally established in 1872 as 42 US gallons.