Pokemon name meaning:
鞠 mari – ball
マリン marin – marine (Japanese word from English)
瑠璃 ruri – lapis lazuli
Unusually, the official trademarked rõmaji for this name does not have the same pronunciation as the Japanese katakana name. マリルリ transliterates as Mariruri or perhaps Mariruli, but certainly not Marilli.
瑠璃 ruri, like English “lapis lazuli”, can refer either to the stone or to the color of the stone. Here it is the color that is intended. This reference is picked up in the English name Azumarill – the first part referring to the word “azure”, which is derived from “lazuli” (lapis merely means “stone”).