Final answer:
A subscript in mathematics refers to a smaller character or symbol written below the baseline. In scientific notation, subscripts are used to represent the number of atoms or elements in a compound.
Step-by-step explanation:
In mathematics, a subscript has multiple definitions, but the most common one refers to a smaller character or symbol that is written below the baseline.
In scientific notation, subscripts are often used to represent the number of atoms or elements in a compound. For example, in the compound NO2, the subscript 2 indicates that there are two oxygen atoms for every one nitrogen atom.