r

Reading level: hard

Estimated CEFR level: B2 — Upper-Intermediate

Estimated from word frequency; not an official CEFR classification.

Definition

noun a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air
noun (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole
noun the 18th letter of the Roman alphabet

Old English lower case letter r, from 7th century replacement by Latin lower case r of the Anglo-Saxon Futhorc letter ᚱ.

The Regiment had paid Rs. — The Works of Rudyard Kipling: One Volume Edition, Rudyard Kipling
"'Fresh a'r make honey sour. — Nights With Uncle Remus: Myths and Legends of the Old Plantation, Joel Chandler Harris
CÆSAREA (s[)e]s [.a] r[=e]' [.a]), an ancient city of Palestine. — De La Salle Fifth Reader, Christian Brothers

roentgen

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