- the theoretical intrinsic rate of increase of a population, equivalent to the difference between the birth and death rates divided by the number of individuals in the population.
- the 18th letter of the English alphabet, a consonant.
- any spoken sound represented by the letter R or r, as in ran, carrot, or rhyme.
- something having the shape of R.
- a written or printed representation of the letter R or r.
- a device, as a printer's type, for reproducing the letter R or r.
- three R's.
- are: Oysters R in season.
- restricted: a rating assigned to a movie by the MPA indicating that children under the age of 17 will not be admitted to a theater showing the film unless accompanied by an adult.
- radical.
- ratio.
- regular: a man's suit or coat size.
- resistance.
- stage right.
- roentgen.
- rook.
- the 18th in order or in a series.
- the medieval Roman numeral for 80.
- arginine.
- universal gas constant.
- written as superscript ® following a name registered with the U.S. Patent and Trademark Office.
- rabbi.
- railroad.
- railway.
- range.
- rare.
- received.
- recipe.
- replacing.
- residence.
- right.
- rises.
- river.
- road.
- rod.
- royal.
- rubber.
- ruble.
- run; runs.
- rupee.
- (in prescriptions) take.
- rabbi.
- Radical.
- radius.
- railroad.
- railway.
- (in South Africa) rand; rands.
- Réaumur.
- rector.
- redactor.
- regina.
- Republican.
- response.
- rex.
- river.
- road.
- royal.
- ruble.
- rupee.
- stage right.
- the 18th letter and 14th consonant of the modern English alphabet
- a speech sound represented by this letter, in English usually an alveolar semivowel, as in red
- See three Rs
- radical
- currency
- rand
- rupee
- Réaumur temperature (scale)
- resistance
- roentgen or röntgen
- rook
- Royal
- gas constant
- (in the US and Australia)
- restricted exhibition (used to describe a category of film certified as unsuitable for viewing by anyone under the age of 18)
- (as modifier)
- rare
- recto
- rod (unit of length)
- ruled
- run(s)
- registered (trademark)
- right
- river
- rouble
- rabbi
- rector
- Regina
- Republican
- response (in Christian liturgy)
- Rex
- River
- Royal