The term "a2" can refer to various concepts depending on the context. In the realm of technology, it often denotes a specific version or model of a product, such as a smartphone or software. In the context of education, "A2" is a level in the Common European Framework of Reference for Languages (CEFR), indicating an elementary proficiency in a language. In the field of genetics, "A2" can refer to a type of beta-casein, a protein found in milk. A2 milk is produced by cows that only carry the A2 variant of this protein, which some studies suggest may be easier to digest for certain individuals compared to A1 milk, which contains a different variant.