The name Amma is a girl's name of African, Ghanan, Ghanaian origin meaning "born on a Saturday". Amma and is often added to lists like Day Names and discussed in our forums with posts like "The Renesmee Name Game".
From the experts:
An anagram of Mama, in tune with its Hindi meaning. Amma is also a Ghanaian name. The Akan people of Ghana and the Ivory Coast frequently name their children after the day of the week they were born and the order in which they were born. Most Ghanaians have a name using this system (think Kofi Annan, whose name means born on a Friday). Amma is the name for girls born on a Saturday. (The name for boys born on a Saturday is Kwame).