n.
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)
3.any of several fat-soluble vitamins essential for normal vision
4.one of the four nucleotides used in building DNA
5.(biochemistry) purine base found in DNA and RNA
6.the basic unit of electric current adopted under the Systeme International d'Unites
7.the 1st letter of the Roman alphabet
Idiom of the Day
make a killing
to make a large amount of money
The woman made a killing on the real estate market before she retired.
