The size of a ceiling fan is described by?

The size of a ceiling fan is defined by the blade span, which refers to the diameter of the circle created by the tips of the rotating blades when the fan is in motion. This measurement is crucial as it directly impacts the air circulation efficiency and cooling capabilities of the fan. A larger blade span typically moves more air, making it more effective in ventilating a space, while a smaller span may be suitable for more compact areas.

In contrast, other options such as blade length only refer to the measurement of an individual blade rather than the complete fan size. Motor amperage pertains to the electrical consumption of the fan motor and does not reflect the physical size or capability of the fan in terms of air movement. Motor volume, which could imply the physical space occupied by the motor, is also unrelated to the fan's operational effectiveness as determined by its size. Therefore, the correct descriptor for the size of a ceiling fan is indeed the blade span.