U
| Pronunciation (US): |   |
Dictionary entry overview: What does U mean?
• U (noun)
The noun U has 3 senses:
1. a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine
2. a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
3. the 21st letter of the Roman alphabet
Familiarity information: U used as a noun is uncommon.
• U (adjective)
The adjective U has 1 sense:
1. (chiefly British) of or appropriate to the upper classes especially in language use
Familiarity information: U used as an adjective is very rare.
Dictionary entry details
• U (noun)
Meaning:
A base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine
Classified under:
Nouns denoting substances
Synonyms:
U; uracil
Hypernyms ("U" is a kind of...):
nucleotide (a phosphoric ester of a nucleoside; the basic structural unit of nucleic acids (DNA or RNA))
Holonyms ("U" is a substance of...):
ribonucleic acid; RNA ((biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell)
Meaning:
A heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
Classified under:
Nouns denoting substances
Synonyms:
atomic number 92; uranium; U
Hypernyms ("U" is a kind of...):
metal; metallic element (any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.)
Hyponyms (each of the following is a kind of "U"):
uranium 235 (a uranium isotope with mass number 235; capable of sustaining chain reactions)
uranium 238 (the commonest isotope of uranium; it is not fissionable but when irradiated with neutrons it produces fissionable plutonium 239)
Holonyms ("U" is a substance of...):
pitchblende; uraninite (a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium; uraninite in massive form is called pitchblende which is the chief uranium ore)
Meaning:
The 21st letter of the Roman alphabet
Classified under:
Nouns denoting communicative processes and contents
Synonyms:
letter u; U
Hypernyms ("U" is a kind of...):
alphabetic character; letter; letter of the alphabet (the conventional characters of the alphabet used to represent speech)
Holonyms ("U" 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)
• U (adjective)
Meaning:
(chiefly British) of or appropriate to the upper classes especially in language use
Similar:
upper-class (occupying the highest socioeconomic position in a society)
Domain region:
Britain; GB; Great Britain; U.K.; UK; United Kingdom; United Kingdom of Great Britain and Northern Ireland (a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland)
