English, French, German and Spanish, derived from Mars, the Roman god of war. It occurs rarely in the 1841 Census of Aberdeenshire.
Note: the Spanish form has the stress on the second syllable: Martín.
As Mark is also possibly derived from Mars, we classify Martin and Mark as lesser synonyms.
Martinus is the Latin form of Martin, used in old documents with appropriate Latin case endings.
The pet name Matty is particularly Scottish, normally being reserved for Matthew.