(The name of) a militant Welsh nationalist organization.
Origin
1960s; earliest use found in The Times. From Welsh meibion, plural of mab son + the name of Owain Glyndŵr, Welsh prince, known in English as Owen Glendower, who fought for Welsh independence from the English.
Definition of Meibion Glyndwr in US English:
Meibion Glyndwr
nounˌmeɪbɪən ɡlɪnˈdʊə
(The name of) a militant Welsh nationalist organization.
Origin
1960s; earliest use found in The Times. From Welsh meibion, plural of mab son + the name of Owain Glyndŵr, Welsh prince, known in English as Owen Glendower, who fought for Welsh independence from the English.