Noun
In Ireland, a tenure of family lands by which the proprietor had only a life estate, to which he was admitted by election.
Source: Webster's dictionaryAs the average life span increased, an eldest son was more likely to reach majority age before the death of his father, and primogeniture became increasingly favoured over proximity, tanistry, seniority and election. Source: Internet
Popular assemblies, as in Ireland, were involved in law-making, and sometimes in king-making, although the introduction of tanistry —naming a successor in the lifetime of a king—made the second less than common. Source: Internet
For tanistry, etc., in Ireland, see Ó Cróinín, Early Medieval Ireland, 63–71. Source: Internet