R

Pronunciation (US):

(GB):

IPA (US):

 Dictionary entry overview: What does R mean? 

• R (noun)
  The noun R has 4 senses:

1. a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air

2. (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole

3. the 18th letter of the Roman alphabet

4. the length of a line segment between the center and circumference of a circle or sphere

  Familiarity information: R used as a noun is uncommon.

 Dictionary entry details 

• R (noun)

Sense 1

Meaning:

A unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air

Classified under:

Nouns denoting quantities and units of measure

Synonyms:

R; roentgen

Hypernyms ("R" is a kind of...):

radioactivity unit (a measure of radioactivity)

Sense 2

Meaning:

(physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole

Classified under:

Nouns denoting quantities and units of measure

Synonyms:

gas constant; R; universal gas constant

Hypernyms ("R" is a kind of...):

constant (a number representing a quantity assumed to have a fixed value in a specified mathematical context)

Domain category:

natural philosophy; physics (the science of matter and energy and their interactions)

Sense 3

Meaning:

The 18th letter of the Roman alphabet

Classified under:

Nouns denoting communicative processes and contents

Hypernyms ("R" is a kind of...):

alphabetic character; letter; letter of the alphabet (the conventional characters of the alphabet used to represent speech)

Holonyms ("R" is a member of...):

Latin alphabet; Roman alphabet (the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe)

Sense 4

Meaning:

The length of a line segment between the center and circumference of a circle or sphere

Classified under:

Nouns denoting attributes of people and objects

Synonyms:

r; radius

Hypernyms ("r" is a kind of...):

length (the linear extent in space from one end to the other; the longest dimension of something that is fixed in place)

Hyponyms (each of the following is a kind of "r"):

semidiameter (the apparent radius of a celestial body when viewed as a disc from the earth)

radius of curvature (the radius of the circle of curvature; the absolute value of the reciprocal of the curvature of a curve at a given point)

Holonyms ("r" is a part of...):

diam; diameter (the length of a straight line passing through the center of a circle and connecting two points on the circumference)

 Context examples 

“This is very kind of you, Mas'r Davy,” said Mr. Peggotty.

(David Copperfield, by Charles Dickens)

The R. mucosa strains included in the treatment were originally isolated from the skin of healthy individuals and grown under carefully controlled laboratory conditions.

(Bacteria therapy for eczema shows promise in NIH study, National Institutes of Health)

This agent also inhibits the receptor tyrosine kinases platelet-derived growth factor receptor (PDGF-R) and c-kit, a receptor tyrosine kinase mutated and constitutively activated in most gastrointestinal stromal tumors (GISTs).

(Nilotinib, NCI Thesaurus)

Also, R&D leading to the ability to design and synthesize, in a controlled manner, nanostructured materials with targeted properties.

(Nanomaterials, NCI Thesaurus)

The minimum duration (time) between successive peaks of R waves in a particular set of RR intervals.

(Minimum RR Duration, NCI Thesaurus)

This was all done _en règle; and in our work we shall be en règle_ too.

(Dracula, by Bram Stoker)

Additionally, GOES-R’s improved rainfall estimates will lead to more timely and accurate flood warnings.

(GOES-R heads to orbit, will improve weather forecasting, NOAA)

Upon administration, astuprotimut-R may stimulate a cytotoxic T lymphocyte (CTL) response against tumor cells expressing the MAGE-A3 antigen, resulting in tumor cell death.

(Astuprotimut-R, NCI Thesaurus)

This allele, which encodes macrophage colony-stimulating factor 1 receptor precursor (CSF-1-R) protein, is involved in the production, differentiation, and function of macrophages and signal transduction that regulates cell fate.

(CSF1R wt Allele, NCI Thesaurus)

Eltrombopag binds to and stimulates the transmembrane domain of the platelet thrombopoietin receptor (TPO-R or CD110), a member of the hematopoietin receptor superfamily.

(Eltrombopag olamine, NCI Thesaurus)