English derivative of and pet name for Mary and also a pet name for Margaret.
May as a given name is now more associated with the fifth month and possibly with the may, the white flower of Crataegus laevigata, the English hawthorn.
A private communication [AB] suggests May as a pet name for Marjory, Margery, Marjorie and Molly. This occurs in some official records and it might be well to consider this when searching. Another correspondent [TL] has an ancestor baptized Margery who was also known as Mary or May, which confirms this connection.
Although there is no clear link, a correspondent [JB 2] recalls that an ancestor baptized Marion was always known as May so we have added this pet name for completeness.