Zeresh was the wife of Haman the Agagite who is mentioned in the Hebrew Bible in the Book of Esther.
Zeresh advised her husband to prepare a high gallows (50 cubits) and to hang Mordechai on it. This plan was reversed when the king later ordered Haman and his ten sons to be hanged on the same gallows which he had prepared for Mordechai.
Although it was written in the Hebrew Bible that Haman and his ten children were hanged on the gallows, it isn't mentioned what became of Zeresh. In a Jewish midrash, however, Zeresh presumed that Haman was riding a horse through the city and being led by Mordecai the Jew. So Zeresh dumped garbage on the man leading the horse which actually ended up being Haman so she jumped out the window and killed herself.