Similar notation is standard in linguistics (and probably other fields too): https://en.wikipedia.org/wiki/Kinship_terminology#Abbreviations_for_genealogical_re

Similar notation is standard in linguistics (and probably other fields too): https://en.wikipedia.org/wiki/Kinship_terminology#Abbreviations_for_genealogical_relationships https://en.wikipedia.org/wiki/Kinship_terminology#Abbreviati.... e.g. ‘Maternal grandmother's son's daughter’ would be MMSD.