Akathistos means hymn in Greek. There are many akathist in the Greek Orthodox church but when usually referred only by an Akathist is to the Mother of God.
The hymn is written in 24 stanza (paragraph) each for every letter of Greek alphabet.
It's one of the most beautiful and beloved hymns to the Mother of God in the eastern tradition together with the Agni Parthene.
It has been translated in many languages so pilgrims from all over the world can pray and reflect on these words.
Tradition says that it was created by Romanos the Melodist in Constantinople in the VI century.
Make sure you honor the Mother of God with this daily prayer.