1. Jewish (Ashkenazic): patronymic from a reduced form of Meyer 2, + German Sohn ‘son’.
2. French: metonymic occupational name for a trader, from Old French mers (Latin merx) ‘wares’, ‘merchandise’.
3. Scottish: probably a metronymic from a short form of the female personal name Mary (see Marie).
See the Key to the Dictionary or consult the General Introduction for further explanation.