angstrom, angstrom unit, A -- (a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation)
vitamin A, antiophthalmic factor, axerophthol, A -- (any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes)
deoxyadenosine monophosphate, A -- (one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose))
adenine, A -- ((biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA)
ampere, amp, A -- (the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps")
(Sound)
