Compact disc - recordable; a form of digital media that is based on the use of a laser to read from and write to a plastic disc. It can only be written to once, although the entire disc does not necessarily have to be written in one session.

a Soviet rocket modelled on the V-2; the Scunner

Resistance-value - A measure of thermal resistance used in domestic insulation.

(slang, humorous) Ritalin, an amphetamine-like psychopharmaceutical, prescribed for ADHD.

(physics, astronomy) The relatively rapid nucleosynthesis process, in supernovae, in which a large neutron flux allows rapid neutron capture and synthesis of elements up to the transuranic elements.

(organic chemistry) A crystalline sulfonic acid, HOC₁₀H₅(SO₃H)₂, derived from beta naphthol and used as a dye intermediate; 2-naphthol-3,6-disulfonic acid.

(algebra) The monoid action of a ring R on an abelian group.

plural of r-word

(euphemistic) The word rape, regarded as a vulgar or taboo word. / (euphemistic) The word retard, regarded as a vulgar or taboo word.

(phonology) The omission of the sound of a letter "r" after a vowel.