Dorea Black

Dorea Potter (née Black) (1920 - 1977) was a pure-blood witch, the youngest child of Cygnus Black II and Violetta Bulstrode and sister of Pollux Black, Cassiopeia Black, and Marius Black. She married Charlus Potter and the together had one son. Dorea was also the aunt of Walburga Black, thus the great-aunt of Sirius Black and Regulus Black.

Etymology
The name Dorea may come from the names Dora ("gift") or Dorothy, which mean "gift of God" in Greek, or from dory, a type of small boat. Name "Dora" appears before Dorea: her great-aunt was named Elladora and her cousin was named Callidora.

Behind the scenes

 * There is some speculation that Dorea Potter was the mother of James Potter and the paternal grandmother of Harry Potter, given that J. K. Rowling has said that James's parents were older when they had him, and Dorea would have been forty years old when he was born . However, Rowling also said that James's parents died of natural causes when they were elderly, presumably around the same time . Dorea died at the age of fifty-seven , which is not elderly in wizarding terms. This may be a mathematical error, as Rowling has also admitted that maths is not her strong suit and inconsistencies have been noted in the timeline.
 * Also, if Dorea was James' mother, James would be the first cousin of Cygnus Black III and Pollux Black (who are about a generation older than James) and second cousin of Cygnus' daughters (Narcissa, Bellatrix and Andromeda) and Pollux's sons Regulus and Sirius who attended Hogwarts around the same time as James.
 * Another possibly is that Dorea was an aunt (via marriage) or a distant cousin-in-law to James. If so, then this leaves us with the mystery of what happened to the son of Charlus and Dorea. Since Harry was not supposed to have any living family other than the Dursley family, we could assume that Charlus, Dorea, and their son must have died before 1981.
 * However, it is also unlikely that Dorea is James Potter's mother as James' parents took Sirius Black into their home after he ran away from his family. As Alphard Black (Sirius' uncle and also Dorea's nephew) was disowned for simply giving Sirius "a decent amount of gold" when he ran away, it's likely that Dorea would also have been disowned for allowing Sirus to live with them.
 * Also, if Dorea and Charlus where the mother and father of James surely he woud have been disowned for marrying Muggle-born Lily Evans, however from what we have heard of the Potter family, they were not averse to mixing pure and muggle blood unlike the Blacks.

Appearances

 * Harry Potter and the Order of the Phoenix (film)

Notes and references
Dorea Black