Load can be anything that will put a certain amount of resistance on the motor. In the case you are reading, they are talking about an airplane prop. Air props will load up a motor to a much larger degree than cars, or even boats.

Also that specific motor is a lower wound higher current draw motor that will spin many RPM's but suffers in torque. There are many reasons to the numbers that you are seeing.

I'm not sure about the free RPM staed on the site vs your box.

Ryan