adult name; name taken upon coming of age
Historical term for the name a person adopted at their coming-of-age ceremony (genpuku), replacing their childhood name. Rare in modern usage outside historical contexts.
Heian-period nobles received an adult name at their coming-of-age ceremony.
元服 is the coming-of-age ceremony itself, while 烏帽子名 is the name taken during that ceremony.
幼名 is the childhood name that is replaced by the 烏帽子名 at adulthood.
From 烏帽子 (eboshi, a type of headgear worn during the coming-of-age ceremony) + 名 (na, name). The exact historical derivation is uncertain, but the term is associated with the Heian-period practice of taking a new name at genpuku.