I had originally read in a Japanese slang dictionary that the word "merikuri" was not in use until BoA's single. I searched again, and found this:

メリクリとは、「メリー・クリスマス」の略で、主に携帯メールで使われた言葉である。
パソコンと違い、携帯電話でメールの文字を打つのは時間がかかるため、簡略出来る言葉はどんどん簡略化され ている。そういった中で生まれた「メリクリ」のような言葉は若者を中心に会話の中でも使われる ようになる。
また、メリクリはBoAがシングル曲のタイトルとしても使っている。

It says Merikuri is basically internet/cellphone shorthand, and was "used as the title for a BoA single." Regardless of the word's origin, my point was that BoA likes shorthand, abbreviations, and creative catchwords. They are used often in her lyrics and titles, like "B.I.O", "ID; Peace B", MOTO, NO.1, and P.O.L, just to name some.


But just because Quincy is a person's name, it doesn't make it particularly significant to the song. I look at titles such as "VALENTI" and "QUINCY" as random, because the content of the songs don't really offer much evidence as to why the title was chosen. They are awkward, and just feel like uncommon words used because the song needed a name, or because the writer wanted his own little inside secret.

J-Pop in general has a lot of very random titles.