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
a-scan ultrasonography
- n the use of ultrasonography to measure the length of the eyeball
a-team
- n a group of elite soldiers or a leadership group of advisors or workers in an organization
a. a. michelson
- n United States physicist (born in Germany) who collaborated with Morley in the Michelson-Morley experiment (1852-1931)
a. conan doyle
- n British author who created Sherlock Holmes (1859-1930)
a. e. burnside
- n United States general in the American Civil War who was defeated by Robert E. Lee at the Battle of Fredericksburg (1824-1881)
a. e. kennelly
- n United States electrical engineer noted for his work on the theory of alternating currents; independently of Oliver Heaviside he discovered the existence of an atmospheric layer that reflects radio waves back to earth (1861-1939)
a. noam chomsky
- n United States linguist whose theory of generative grammar redefined the field of linguistics (born 1928)
a. testudineus
- n a small perch of India whose gills are modified to allow it to breathe air; has spiny pectoral fins that enable it to travel on land