Responses
Because Haruaki wrote his name in the blackboard and the Onyomi pronunciation of (Abe) Haruaki- (安) 晴明 is Seimei.. Mame mispronouced the name and it stuck..
So his name is actually Seimei.. Just a different pronunciation.. It was explained in one chapter why his parents named him Haruaki. It was because it was raining (Ame) when they were born and the skies cleared up/brightens (Haru).
But does it occur to anyone that why did mame called haruaki, seimei and not haruaki?? Like not a single person knows that he was from the family of Abe no seimei. But still mame called harauki seimei