(From Vocaloid Wiki):

GUMI (グミ) is a Japanese VOCALOID developed and distributed by Internet Co., Ltd. as Megpoid (メグッポイド), which was initially released June 2009 for the VOCALOID2 engine. There has since been three installments developed for the VOCALOID3 engine, one that includes an update of the VOCALOID2 voice bank. She has been updated to the VOCALOID4 engine in November 2015. Her voice is provided by Filipino-Japanese female singer and voice actress, Megumi Nakajima (中島愛; Nakajima Megumi).

GUMI was the second VOCALOID to be released by the company Internet Co., Ltd and had a more retro-futuristic approach than Gackpo.

"Gumi" is a childhood nickname of Megumi Nakajima,

The software name, "Megpoid", was taken from the provider's name "Megumi." The second half, "ppoid", is a combination of "ppoi" (っぽい: resembling) and "loid": "like Vocaloid". the full implied name of this product is "Megumi-like Vocaloid."

Her design is often said to be influenced by Ranka Lee's character (one of the first roles done by Megumi Nakajima as seiyuu). Ranka Lee's main outfit (which she wears for the notable song Seikan Hikou) contains the colors green, yellow, and orange. This has never been officially confirmed, but is still a popular assumption with both Japanese and overseas VOCALOID fans.

Her belt buckle incorporates the Tenori-on device's design.