Literally it means, "Friendly Ones," perhaps in reference to the outcome of the play. Although, as Gone Jackal pointed out to me, it was more likely simply another name for the Furies to avoid having to say their actual name. Nothing like analyzing a work of fiction until even a paranoid conspiracy-mad nutcase would say you're reaching.

Furies:

Rejoice!-
rejoice - the joy resounds -
all those who dwell in Athens,
spirts and mortals, come,
govern Athena's city well,
revere us well, we are your guests;
you will near to praise your Furies,
you will praise the fortunes of your lives.

No, I don't know why the above text was centered. My translation was typeset by a drunken monkey. If anyone knows why Robert Fagel's translation of Aeschylus's Orestia is typeset by a drunken monkey please, please, please, let me know.