Or your utility may use freedom units like Therms

Ccf is also common because it's the directly measured quantity by your gas provider and you don't need silly charts like https://www.eia.gov/totalenergy/data/monthly/pdf/sec12_5.pdf

Seems odd to sell a gas by volume though... are these understood to be at a standardized pressure/density?

My gas bill each month lists the correction factor used for that month to compensate the meter reading to the volume consumed (and thus billed) based on the average weather.