Jerilyn is most likely a variant of Geraldine, influenced by Marilyn. Geraldine originates in Germanic languages and means "ruler with spear". It is a feminine form of Gerald. The famous bearer of this name is Geraldine Chaplin, English-American actress and the daughter of Charlie Chaplin. It is also the name of several places in the United States. As a feminine given name its usage has declined lately. Jerilyn is a very rare given name in the United States these days.