BLDC (Brushless DC Motor) vs PMSM (Permanent Magnet Synchornous Motor)
In a BLDC motor, the windings are concentrated on salient poles, so producing a voltage waveform that's more trapeziodal than sinusoidal.

In a PMSM, the windings are distributed over several poles, so producing a  voltage waveform that's more more sinusoidal.

These differences mean that BLDC motors are slightly cheaper to produce, but may be slightly less efficient, noisier and have more cogging, than PMSMs.