Princeton's WordNet

1. degree centigrade, degree Celsius, C(noun)

   a degree on the centigrade scale of temperature

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

2. speed of light, light speed, c(noun)

   the speed at which light travels in a vacuum; the constancy and universality of the speed of light is recognized by defining it to be exactly 299,792,458 meters per second

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, c, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

3. vitamin C, C, ascorbic acid(noun)

   a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

4. deoxycytidine monophosphate, C(noun)

   one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

5. cytosine, C(noun)

   a base found in DNA and RNA and derived from pyrimidine; pairs with guanine

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

6. carbon, C, atomic number 6(noun)

   an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds

   Synonyms:
   century, hundred, degree centigrade, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, carbon paper, deoxycytidine monophosphate, one C, carbon copy, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

7. hundred, 100, C, century, one C(noun)

   ten 10s

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

8. coulomb, C, ampere-second(noun)

   a unit of electrical charge equal to the amount of charge transferred by a current of 1 ampere in 1 second

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

9. C(noun)

   a general-purpose programing language closely associated with the UNIX operating system

   Synonyms:
   century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

   Antonyms:
   ordinal

10. C(noun)

    (music) the keynote of the scale of C major

    Synonyms:
    century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

    Antonyms:
    ordinal

11. C, c(noun)

    the 3rd letter of the Roman alphabet

    Synonyms:
    century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, ascorbic acid, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine

    Antonyms:
    ordinal

12. coke, blow, nose candy, snow, C(adj)

    street names for cocaine

    Synonyms:
    degree centigrade, nose candy, reversal, deoxycytidine monophosphate, light speed, bump, setback, cytosine, snow, coke, vitamin C, shock, black eye, hundred, reverse, century, degree Celsius, ampere-second, coulomb, speed of light, puff, atomic number 6, blow, gust, one C, ascorbic acid, carbon, blast, snowfall

    Antonyms:
    ordinal

13. hundred, one hundred, 100, c(adj)

    being ten more than ninety

    Synonyms:
    one hundred, c, hundred

    Antonyms:
    ordinal