(n.) R, the eighteenth letter of the English alphabet, is a vocal consonant. It is sometimes called a semivowel, and a liquid.

L R acting area airstrip apron stage backstage band shell bandstand bib board bridge clearway coulisse dock dressing room fairway flies flight deck fly floor fly gallery forestage greenroom grid gridiron landing deck landing strip lightboard orchestra orchestra pit performing area pinafore pit proscenium proscenium stage runway shell smock stage stage left stage right strip switchboard the boards tucker wings