Eumenides vs Alecto

Eumenides and Alecto both are nouns.

Word	Noun	Adjective	Verb	Adverb
Eumenides	Yes	No	No	No
Alecto	Yes	No	No	No

As nouns, Alecto is a hyponym of Eumenides; that is, Alecto is a word with a more specific, narrower meaning than Eumenides:

Eumenides: (classical mythology) the hideous snake-haired monsters (usually three in number) who pursued unpunished criminals
Alecto: the one of the three Furies who punishes the moral crimes (such as anger)

Other hyponyms of Eumenides include Megaera, Tisiphone.

Eumenides (noun)	Alecto (noun)
(classical mythology) the hideous snake-haired monsters (usually three in number) who pursued unpunished criminals	the one of the three Furies who punishes the moral crimes (such as anger)