"N2" can have multiple meanings depending on the context.
1. In mathematics, "N2" can refer to the set of natural numbers greater than or equal to 2, i.e., {2, 3, 4, 5, ...}.
2. In chemistry, "N2" represents the chemical formula for nitrogen gas, which is a diatomic molecule consisting of two nitrogen atoms bonded together.
3. In language proficiency exams such as the JLPT (Japanese Language Proficiency Test), "N2" refers to the second level of proficiency, indicating an intermediate level of understanding and usage of the Japanese language.