- A subscript.
- An index of measurement based on relatively few variables, especially a trade index based on the performance of a particular group or type of stocks.
- A specifying figure or letter following and slightly below a figure, letter, or symbol: as the 0 in <em>x</em><sub>0</sub>.
- A number or mark placed opposite the lower part of a letter or symbol to distinguish the symbol.
- A subsidiary <xref>index</xref>, or one that represents a <xref>sector</xref> of a larger one
- A <xref>subscript</xref>