The stall speed or the minimum steady flight speed at which the aeroplane is controllable in 1-g conditions.

The speed at which onset of natural stall warning occurs with the aeroplane NOT exceeding 1-g conditions.

The 1-g stall speed at which the aeroplane can develop lift equal to its weight.

The speed at which onset of artificial stall warning occurs with the aeroplane NOT exceeding 1-g conditions.