When these characters were first created, the name was not "Monokuro Boo", it was "Monotone," with "mono" coming from "monochrome" and "ton," a word for pig.
Kun kyseiset hahmot aluksi luotiin, nimenä ei ollut "Monokuro Boo", vaan "Monotone", jossa "mono" tuli sanasta "monochrome" (yksivärinen, mustavalkoinen) ja "ton" tarkoitti sikaa.