Rich m
English: short form of RICHARD (SEE Richard). There was a medieval name Rich(e), but it is connected only indirectly with the modern form: it represents a short form of several medieval names, including not only Richard but also other, rarer names of Norman (Germanic) origin with the same first element, as, for example, Rich(i)er ‘power army’ and Richaud ‘power rule’. It also came to be used as an independent baptismal name in the 15th century.
First names dictionary. 2012.