1. Similar to "Brother From Another Mother", this describes a female friend that has grown such a strong emotional bond with a different family that she appears to be or could be considered to be part of that family, despite having no blood relation.
2. A step-sister that has resulted from having two different fathers.
Suzy: I love Katie. She's my best friend and I couldn't live without her. My parents love her, too. She's my sister from another mister.
by IQuarent August 6, 2013
Plural: Sisters From Other Misters

The female equivalent of Brother From Another Mother, this term is used by two or more female friends as a term of friendly endearment towards each other because they are so close, they are practically sisters. A Sister From Another Mister is there for the other Sister 24/7, no matter what.
Eve and Kat have been friends since the summer of 2010. Eve has been there for Kat to support her through almost everything. Kat can call Eve any time of day or night, so long as it's before 9 PM, but that is only because Eve's parents don't like calls after then. Even though Eve and Kat are almost complete opposites, they still remain friends and will be there for each other until the end. Eve and Kat call each other Sister From Another Mister.
by Gothically Raised Eyebrow October 23, 2013
The same as "brother from another mother", but it doesnt rhyme as well. What a gril or boy will say to a close girlfriend, Sister used because the girl is very close to them, another mister is used because the girl is born to a different father.
"Hey my sista from another mista!"
by diseased sheep June 28, 2005