Cord

One hundred and twenty-eight cubic feet of stacked firewood, being a pile four feet high, four feet deep and eight feet long.

The cord measures the stack rather than the wood, so the air between the logs is included in what the buyer pays for. That sounds like a swindle until you consider the alternative: measuring the true volume of a heap of irregular billets would require either water displacement or a great deal of trust. Stacking to a fixed frame is checkable by anyone with a tape. The name comes from the cord once used to bind the stack for measurement. It remains the standard firewood measure in North America, though British practice more often used the load or the stack of 108 cubic feet.