It is just confusing to use the same word to suggest explicit assistance (cash, tax breaks, etc) and "failure to penalize". I guess mathematically they both re

It is just confusing to use the same word to suggest explicit assistance (cash, tax breaks, etc) and "failure to penalize". I guess mathematically they both represent a reduction in cost when compared to an alternative scenario (no subsidy and some sort of tax/fee for the externality) but they are different mechanisms and so it makes sense for them to have different words to describe them if you want to communicate clearly.