A

noun

1.
a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
angstrom angstrom unit
2.
any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
antiophthalmic factor axerophthol vitamin A
3.
nucleotide derived from adenine with a deoxyribose sugar and a phosphate group
dAMP deoxyadenosine monophosphate deoxyadenylate deoxyadenylic acid
4.
(biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
adenine
5.
the basic unit of electric current adopted under the Systeme International d'Unites
amp ampere
6.
the 1st letter of the Roman alphabet
a
7.
the blood group whose red cells carry the A antigen
group A type A