menarche
men·ar·che
noun \ˈmen-ˌär-kē\Definition of MENARCHE
: the beginning of the menstrual function; especially : the first menstrual period of an individual
—men·ar·che·al \ˌmen-ˈär-kē-əl\ or men·ar·chal \men-ˈär-kəl\ also men·ar·chi·al \men-ˈär-kē-əl\ adjective
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