According to Collins english Dictionary's etymology, this is the origin, Sam.
American Heritage Dictionary gives a very similar result.

n
(Cookery) a preserve made by boiling the pulp and rind of citrus fruits, esp oranges, with sugar
adj
(Fine Arts & Visual Arts / Colours) (of cats) streaked orange or yellow and brown
[via French from Portuguese marmelada, from marmelo quince, from Latin, from Greek melimēlon, from meli honey + mēlon apple]

I'm immortal until proven otherwise