User blog comment:ChishioKunrin/Should we have a page about Remnant's naming rule?/@comment-25405817-20150207142000/@comment-4010415-20151013154045

Seriously, a penny is a coin that's coated in copper, and copper turns green when it oxidizes. Penny's name is easy - copper and green, which explains her hair color, eye color, and why she has so much green on her clothes.