A2

Etymology

 * Specified in.

Noun

 * 1)  A type of Asian influenza virus.
 * 2)  Aortic second sound.
 * 1)  Aortic second sound.

Etymology
See the Wikipedia article ISO 216, the international standard on paper sizes.

Noun

 * 1) A standard paper size, defined by ISO 216.
 * dimensions: 594 x 420 mm