Rom. Romans.
Rom. Cath. Roman Catholic.
R.P. Reformed Presbyterian; Regius Professor.
R.R. Right Reverend.
R.R.C. Royal Red Cross (for ladies).
R.S. Royal Society.
R.S.A. Royal Society of Antiquaries; Royal Scottish Academy or Academician.
R.S.D. Royal Society of Dublin.
R.S.E. Royal Society of Edinburgh.
R.S.L. Royal Society of London.