See, for example, https://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric#Newtonian_interpretation and the image caption at https://en.wikipedia.org/wiki/Amplitude#Definitions.
Reported at https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Truncated_math_expressions_on_Edge