An Irish Republican paramilitary organization, formed in December 1969 from a schism within the IRA, with the aim of creating a united socialist Ireland.
Origin
1970s; earliest use found in The Guardian.
Definition of Official I.R.A. in US English:
Official I.R.A.
noun
An Irish Republican paramilitary organization, formed in December 1969 from a schism within the IRA, with the aim of creating a united socialist Ireland.