Lennon, ó Luinín This anglicised form may be the translation of a number of Gaelic surnames. An important sept of which was ó Luinín meaning descendant of Luinín, diminutive of Lon, meaning ‘a blackbird’. A sept of Fermanagh who were erenaghs of Derryvullen. In 1890 Lennon was principally found in Dublin and Armagh and the estimated number of bearers was 4,610.