a word, letter, number, or symbol written or printed just below another word, letter, number, or symbol, usually in a smaller size

Format the figure one in superscript and the figure three in subscript. 图一用上标格式，图三用下标格式。

The subscripts s and m denote respectively quantities downstream and upstream of the shock. 下标s和m分别表示激波下游和上游的量。

subscript figures 下标数字