R.S.M. Royal School of Mines.
R.S.O. Railway Sub-office; Railway Sorting Office.
R.S.S., also S.R.S., Regiæ Societatis Socius=Fellow of the Royal Society.
R.S.V.P., Répondez, s'il vous plait (Fr.)=Reply, if you please.
Rt. Hon. Right Honourable.
Rt. Rev. Right Reverend.
R.T.S. Religious Tract Society.
Rt. W., Rt. Wpful. Right Worshipful.
R.V. Rifle Volunteers; Revised Version.
R.W.D.G.M. Right Worshipful Deputy Grand Master.