a
- n a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
- n any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
- n one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
- n (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
- n the basic unit of electric current adopted under the Systeme International d'Unites
a typical household circuit carries 15 to 50 amps - n the 1st letter of the Roman alphabet
- n the blood group whose red cells carry the A antigen
a'man
- n the Israeli military intelligence which produces comprehensive national intelligence briefings for the prime minister and the cabinet
a-bomb
- n a nuclear weapon in which enormous energy is released by nuclear fission (splitting the nuclei of a heavy element like uranium 235 or plutonium 239)
a-line
- n women's clothing that has a fitted top and a flared skirt that is widest at the hemline