The name Étaín (Old Irish pronunciation: [ˈeːdainʲ]) is alternately spelt as Edain, Aideen, Etaoin, Éadaoin, Aedín, or Adaon.

However, the poem embedded in the text, "A Bé Find in ragha lium" may be an older, unrelated composition that was appended to the story later.

[5] Similarly, the Etain mentioned in the Second Battle of Moytura is the mother of Carpre the poet who satirizes and shames the Fomorians.

First Fúamnach turns Étaín into a pool of water, then into a worm, (in some versions a snake) and then into a beautiful scarlet fly.

Fúamnach then creates a wind that blows the fly away and does not allow it to alight anywhere but the rocks of the sea for seven years.

The wine is swallowed (together with the fly) by the wife of Étar, an Ulster chieftain, in the time of Conchobar mac Nessa.

Eventually he admits to Étaín that he is dying of love for her, and she agrees to sleep with him to save his life.

They arrange to meet, but Midir casts a spell which causes Ailill to fall asleep and miss the assignation.

Eochaid, warned by his foster-father that Midir is a being of great power, sets him a series of tasks, including laying a causeway over Móin Lámrige, which he performs reluctantly.

The next day fifty women who all look like Étain appear, and an old hag tells Eochaid to choose which one is his wife.

The Dindsenchas poem on Rath Esa recounts how Eochaid Airenn won back Étaín.

The Middle Irish text Togail Bruidne Dá Derga (Recension II) includes a rather lengthy and colourful depiction of her in the episode of her encounter with King Echu in Brí Léith: [...] con-accai in mnaí for ur in tobair & cír chuirrél argit co n-ecor de ór acthe oc folcud a l-luing argit & ceithri h-eóin óir furri & gleorgemai beccai di charrmogul chorcrai h-i forfleascuib na luingi .

Léne lebur-chulpatach isí chotutlemon dei sítiu úainide fo derginliud óir impi.

Taitned fria in grían co b-ba forderg dona feraib tuídhleach ind óir frisin n- gréin asin títiu uainidi.

"[11] In equally rapturous style, the narrator proceeds to home in on her physical beauty: Is and buí oc taithbiuch a fuilt dia folcud & a dá láim tria derc a sedlaig immach.

Ba gilithir úan tuindi in taeb seng fota tláith mín maeth amal olaind.

Cid ríagail fo-certa forsna traigthib is ing má 'd-chotad égoir n-indib acht ci tórmaisead feóil ná fortche foraib.

Tibri ániusa ceachtar a dá grúad, co n-amlud indtibsen do ballaib bithchorcra co n-deirgi fola laíg, & araill eile co solusgili sneachta.

Ba sí trá as caemeam & as áildeam & as córam ad-connarcadar súili doíne de mnáib domain .

[12] "At the well, the woman loosened her hair in order to wash it, and her hands appeared through the opening of the neck of her dress.

As white as the snow of a single night her wrists; as tender and even and red as foxglove her clear, lovely cheeks.

As white as sea foam her side, slender, long, smooth, yielding, soft as wool.

If a rule were put against her feet, scarcely a fault would be found save for her plenitude of flesh or skin.

The blushing light of the moon in her noble face; an uplifting of pride in her smooth brows; a gleam of courting each in her two royal eyes.

Margaret Dobbs has noted the parallel of the three cups offered by Medb to the Ulster heroes in Fled Bricrenn.

Moreover, she points out a possible relationship to examples of late Hallstatt pottery and bronzeware from Central Europe in which figures of aquatic birds were attached to bowls or vases, whether they were specifically designed for religious ceremonies or conveyed religious ideas in more general contexts.

[14] Aideen's Grave is a megalithic portal tomb located in Binn Éadair, according to legend this was her final resting place.