MEIKO is a humanoid persona voiced by a singing synthesizer application called Vocaloid developed by Yamaha Corporation. Her voice is sampled by Meiko Haigo. She has performed at live concerts onstage as an animated projection along with Crypton Future Media's other Vocaloids (like Hatsune Miku). She was the fourth Vocaloid ever released and the first to sing in Japanese.

The name of the character comes directly from her voice provider's name, “Haigo Meiko.” MEIKO's codename was “Hanako” – it likely came from “Yamada Hanako,” a placeholder name for female characters, and the Japanese equivalent to “Jane Smith.” “Megumi” was also a name considered during her development.