首页英语词典aa英英释意

a

英 [ə; eɪ] 美[e]
  • n. 字母A;第一流的;学业成绩达最高标准的评价符号
  • abbr. [物]安(ampere)

英英释意


1. the blood group whose red cells carry the A antigen
2. a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
3. any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
4. one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
5. (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
6. the basic unit of electric current adopted under the Systeme International d'Unites;
"a typical household circuit carries 15 to 50 amps"
7. the 1st letter of the Roman alphabet