R, or r, a liquid consonant, being the 17th letter of our alphabet. Its sound is formed by a guttural extrusion of the breath vibrated through the mouth, with a sort of quivering motion of the tongue drawn from the teeth, and canulated with the tip a little elevated towards the palate. In Greek words it is frequently aspirated with an h after it, as in rhapsody, rhetoric, &c. otherwise it is always followed by a vowel at the beginning of words and syllables.
In the notes of the ancients, R, or RO, signifies Roma; R. C. Romana civitas; R. G. C. rei gerendæ causa; R. F. E. D. recte factum et dictum; R. G. F. regis filius; R. P. res publica, or Romani principes, and R. R. R. F. F. R. res Romana ruerit ferro, fame, flamma.
Used as a numeral, R anciently stood for 80; and with a dash over it thus , for 80,000; but the Greek
, , with a small mark over it, signified 100; with the same mark under it, it denoted ; thus
signifies 100,000. In the Hebrew numeration denoted 200; and with two horizontal points over it denoted ; thus = 200,000.
In the prescriptions of physicians, R or Rs stands for recipe, i. e. "take."