A2

noun

British an advanced level of a subject taken for the General Certificate of Education, forming the second part of an A level course, after the AS level

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Examples from the Web for a2

A2 seemed the most promising, but A3 could also have potential, so I would carry these two options on to the next level.
A Mathematically Impossible Novel: Manil Suri Explains “The City of Devi”|Manil Suri|March 15, 2013|DAILY BEAST
Title with ornament containing an open book, A2 (verso blank).
A Catalogue of Books in English Later than 1700 (Vol 2 of 3)|Various
Let us next examine the eighth term (A2) and see how it is formed.
An Introduction to the Study of the Maya Hieroglyphs|Sylvanus Griswold Morley
There is, to aid imagination, a definite corporal effect due to a2 slight change in the nature of the air.
Switzerland|Frank Fox

At the surface of the ground there is no inequality of level—the beds overlying the coal (a2) having been removed by denudation.
Fragments of Earth Lore|James Geikie
The values of a2 at the various stations differ comparatively little, and show but little seasonal change.
Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 8|Various