Primogeniture (/ˌpraɪm-ə-/ also /-oʊ-ˈdʒɛnɪtʃər/) is the right, by law or custom, of the firstborn legitimate child to inherit the parent's entire or main estate in preference to shared inheritance among all or some children, any illegitimate child or any collateral relative. In most contexts, it means the inheritance of the firstborn son (agnatic primogeniture); it can also mean by the firstborn daughter (matrilineal primogeniture).