eɪ̯ eɪ̯ ˈæ.dəˌniːn æmp ˈæmˌpɪər ˈæmˌpɛər ˈæŋstɹəm ˈæŋstɹəm ˈæŋstɹʌm the blood group whose red cells carry the A antigen the 1st letter of the Roman alphabet the basic unit of electric current adopted under the Systeme International d'Unites a typical household circuit carries 15 to 50 amps a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA nucleotide derived from adenine with a deoxyribose sugar and a phosphate group any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes