Motown: a group of black singers and songwriters on the Motown record label (from MotorTown, Detroit). This was a type of soul music, lyrical and tuneful, using 'horn' sections (trumpets, trombones and saxophones) as well as the bass guitar which was now used in all popular music. Examples are Smokey Robinson and Diana Ross.
Soul: based on the Atlantic coast of the US, soul music was also lyrical but somewhat more aggressive than Motown. Examples are Wilson Picket and James Brown.