ex ‧ po ‧ nen ‧ tial /ˌekspəˈnenʃ ə l◂/ BrE AmE adjective technical
1 . exponential growth/increase etc exponential growth, increase etc becomes faster as the amount of the thing that is growing increases:
an exponential increase in travel
2 . using a small number or letter slightly above and to the right of a number or letter that shows how many times a quantity is to be multiplied by itself
—exponentially adverb