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
in proportion
having the right or wrong proportion in relation to something else
We tried to make sure that the bookshelves were both in proportion when we rebuilt the house.