a - definitions and synonyms

a noun

  1. ( also written as A )

    English Meaning: 

    : a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation

    Synonyms:

    angstrom / angstrom unit
  2. ( also written as A )

    English Meaning: 

    : any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes

  3. ( also written as A )

    English Meaning: 

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

  4. ( also written as A )

    English Meaning: 

    : (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA

    Synonyms:

    adenine
  5. ( also written as A )

    English Meaning: 

    : the basic unit of electric current adopted under the Systeme International d'Unites

    Example Sentenses:

    • a typical household circuit carries 15 to 50 amps

    Synonyms:

    amp / ampere
  6. ( also written as A )

    English Meaning: 

    : the 1st letter of the Roman alphabet

  7. ( also written as A )

    English Meaning: 

    : the blood group whose red cells carry the A antigen

    Synonyms:

    group a / type a