English, the medieval Anglicized variant of Marie, the French form from the Latin Maria. Originally from the Hebrew, Miriam/Mariamne, possibly meaning "wished for child" [Whyte] or "star of the sea" [ONC].
Another source, "The Baby Names Guide" gives the meaning of all three names as "Sea of Bitterness" and Mariam may also mean "rebellious".
Mary occurs frequently in the New Testament: Luke 10:38-42; John 11:1-46 & 12:1-9; Collossians 4:10, Romans 16:6.
See Maria for other variants and pet names.
In old documents in Latin, Maria is used, with appropriate case endings, for Mary or Marie.
Note that the 1841 Census of Aberdeenshire and the 1851 Census of Rathen parish have significant occurrences of the spelling Marey.
A correpondent [RB] has noted the respelling of Meran or Merran as "Mary Ann" in Sutherland, Scotland so it is possible that these names have been derived in this way.
The pet name Molly is English and non-Gaelic Irish and is sometimes used as a given name. It is derived from the earlier pet name Mally.
Polly as a Pet Name is derived from Molly and has been found in some records [GM]. Its use as a widely-used pet name for Mary is supported by another correspondent [MB] who sent us a transcription of a letter dated 1796 in North Carolina, USA. In the letter a child named Mary is frequently referred to as "Polly".
Minnie as a nick-name for Mary is widespread in some communities and often reduced to Min.
NB From personal observation, we believe that the abbreviation Marg [for Margaret] has, on rare occasions, been transcribed as Mary in some on-line sources, so care may be needed when searching on-line services.