D defs.my
Entry 1 sense Webster, 1913

R

/(är)/ · IPA /ɑɹ/
01 R, the eighteenth letter of the English alphabet, is a vocal consonant. It is sometimes called a semivowel, and a liquid. See Guide to Pro…
  1. 1.
    R, the eighteenth letter of the English alphabet, is a vocal consonant. It is sometimes called a semivowel, and a liquid. See Guide to Pronunciation, §§ 178, 179, and 250-254.
Phrases & compounds
The three Rs — a jocose expression for reading, (w)riting, and (a)rithmetic, -- the fundamentals of an education.