Aurora Sinistra was a professor of Astronomy at Hogwarts.
Aurora = L. goddess of the dawn
"sinistra" = Latin for "with the left hand." For Ancient Greeks and Romans the left side symbolized unfavorable omens and perverseness (Lewis & Short).
"Sinistra" = the name of a magnitude 3.5 star in the constellation Ophiuchus, the Serpent Handler (Fixed Stars).
Professor Sinistra's first name 'Aurora' is given in an early planning draft for Prisoner of Azkaban available on JKR's website. However, we cannot consider this verified canon because other information on this page changed by the time the book was actually published (JKR).
On an earlier manuscript, Rowling referred to Sinistra as "Aurelia."
The question of Sinistra's gender came up during the translation of Order of the Phoenix into Portuguese. The translation team contacted the Lexicon for an answer to the question, but I couldn't answer for sure, since it never says one way or the other in the books (although many did point out that Sinistra danced with Moody at the Yule Ball, which strongly implied that the professor was female). I suggested that they contact Rowling, which they did. Rowling's reps responded that Sinistra was in fact a woman.