After Zeus changed Io into a heifer, Hera saw her and sent a gadfly to chase her out of Greece. She fled across the Mediterranean to Egypt, where she arrived on the sand from the ocean. The Egyptians thought she was divine, so they worshipped her. After a while, Hera forgave her and turned her back into a girl, and the son she had became the first Egyptian Pharaoh.
In a way, this is a cool name: only two letters, yet it's technically two syllables, and it looks cool, kind of like number 10. But it is a bit minimalist for my taste. However, it sounds pretty cool pronounced ''IE-o'', whereas the pronunciation ''EE-o'' strikes me as absolutely atrocious and reminds me of horses and annoying children's songs from several decades back for some reason. Please make sure you pronounce it ''IE-o'' if you use it, at least that way it sounds like the awesome names Iona and Ione.
When I first heard this name, I did immediately think of I.O.U., or that I owed somebody something. But this is one of those names that grows on you. It's only two vowels, but they do carry an impact--you don't forget meeting a girl/woman named Io. Therefore, I don't think it's too short. In fact, I would seriously consider using this name.
Io (Ιώ), pronounced EE-Oh, was a mythological figure. She was a priestess of Era (Hera in English) in Argos.
Zeus seduced the young woman and afterward turned her into a young virgin cow (heifer), to help her escape Hera's rage of jealousy. Unfortunately Hera did found her and captured her. She set a guard for Io, a very frightful Giant, a monster called Argos (were the area got it's name from).
Argos had 100 eyes all over his body and was a sleepless guard because when half his eyes were closing for sleep the other half stayed open. He was the one that slayed another mythological monster, Echidna.
Hermes, after Zeus's order, dressed up as a shepherd and by playing his music instrument lira he made Argos fall completely asleep and killed him, setting Io free. Hera however send Io a gadfly to sting her all over the world until she jumped in the sea. The Ionian sea was named after her.
Io is the innermost of the four Galilean moons of the planet Jupiter.
Antonio da Correggio's 1530 painting "Jupiter and Io" represents the love affair.
Io (Ηώ or Εώ, or Αυγή in modern Greek) is another mythological figure, she was the goddess Dawn in English or Aurora in Latin. She was the beautiful daughter of Titans and her job was to open the gates of the sky for God Sun (Helios / Ήλιος, and not Apollo as many say) to come out with his chariot. She was wearing a dress the colour of saffron or krokus, and had rosy finger. She was spraying morning dew on earth.
Yes, Zeus did change Io into a cow, and Hera sent a fly to follow her all over the world, but I believe she was eventually turned back into a human, and Hercules (Herakles in Greek) descended from her about 11 generations later.
In English, the name is pronounced EYE-Oh, at least the moon of Jupiter is pronounced this way. I think it is beautiful, but only when pronounced like this.