On is the son of Peleth, of the Tribe of Reuben was a participant in Korah’s rebellion against Moses according to Numbers 16:1. The meaning of this name is "potency", "strength", "power".
From Japanese 恩 (on) meaning "grace, kindness, goodness, favor, mercy, blessing, benefit", 温 (on) meaning "warm", 音 (on) meaning "sound" or other kanji which are pronounced the same way.