The clones are orphans. Sarah was raised by Mrs. S. Helena was raised by the Ukrainian nuns. Rachel was raised by Ethan and Susan. Cosima and Alison…not much has been said.
But anyway…the reference of it being "black" refers to the fact that the clones had to be hidden. When Mrs. S is explaining to Sarah about her past when Sarah was very young about Carlton:
-Mrs. S : "...Sometimes his pipeline would bring in a child in the black, a child to hide. You were one of them.
-Sarah: "Why'd he have to hide me?"
-Mrs. S: "We didn't ask what we didn't need to know. I had the chance to legitimize a child, so I became your legal guardian. The last time I heard from Carlton, he was about to be arrested and he warned me, he begged me, to move you away, to hide you deeper."
So, Mrs. S knew that there was something about Sarah that made it very dangerous if she was discovered. We learn, of course, the reason is that she's a clone. Her entire biology has been patented. We also know that Sarah's surrogate mother, Amelia, became suspicious about everything that was going on, so she ran away to give birth in secret to protect the lives of Sarah (and Helena). We're to assume that Carlton knew this fact, and that he knew her identity needed to be concealed, for her to have the right to live a free life.
So, I think "Orphan Black" is sort of like a shortened way of saying "An orphan from the 'black'". Like, the children from the unknown, whose identities are concealed, who need to cover their tracks, whose backgrounds are mysterious.
because she's an orphan and she's black
jk I d k
here is a link that tells it all http://orphanblack.wikia.com/wiki/Orphan...