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Establishment of the menstrual function; the time of the first menstrual period. [G. men, month, + arche, beginning]
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men·ar·che 'men-.är-kē n the beginning of the menstrual function esp the first menstrual period of an individual
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n.
the start of the menstrual periods and other physical and mental changes associated with puberty. The menarche occurs when the reproductive organs become functionally active and may take place at any time between 10 and 18 years of age. Compare gonadarche.
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me·nar·che (mə-nahrґke) [men- + Gr. archē beginning] the establishment or beginning of menstruation. menarchal, menarcheal, menarchial adjMedical dictionary. 2011.