In Euripides' Medea, several women other than Medea are represented. We have Medea's nurse, who delivers the prologue; the women of Corinth, who make up the Chorus; and Creon's daughter, who does not appear on stage, but whom the playwright describes.
On a basic level, some of these women are Greeks and some of these women are barbarians (i.e., non-Greeks). Medea is certainly a barbarian and her nurse probably was, whereas Creon's daughter and the women of the Chorus are Greeks who live in Corinth.
This contrast between Greek and barbarian is a significant for Euripides' Athenian audience in 431 BCE, who frequently had contact and conflict with barbarians, especially the Persians in the 490s and 480s. The major difference between Medea and the other women in the play are her dabbling in witchcraft and her willingness to betray or kill her loved ones. These are things that the Greeks might expect barbarians to do. We should also recall that in addition to killing her children, Medea also betrayed her father and killed her brother when she went with Jason. Thus, Jason concludes that
I must have lost my mind to bring you here,
from that savage country, to a Greek home.
(Ian Johnston translation)
Barbarian Medea's killing of her own children is certainly something that the female Greek chorus thinks is impossible. Thus, they ask her, "But, lady, can you stand to kill your children?" These Greek women conclude that such an action will "devastate" her "as a woman" (Ian Johnston translation)
So, the major difference between Medea and the other women in the play is that she has betrayed her country, her father, and killed her brother and her own children. These are the actions of a barbarian, not a Greek.
Medea is different than other women in the play, Medea, because of her vengeful and angry nature. Unlike the other women who behave according to a silent code of conduct, Medea behaves angrily toward her husband and his new wife, acting in cunning ways to seek revenge on them. Medea is often referred to as one of the first feminist plays, as the plot itself explores being a woman in a patriarchal society, something very rare for the time.