This is the 12538th most frequent Spanish word.
millonarias
"Millonarias" means "millionaires" (feminine plural) in English.
Here, 'millonarias' is used as an adjective describing the wealth status of the businesswomen.
Ellas son empresarias millonarias.
They are millionaire businesswomen.
In this sentence, 'millonarias' functions as an adjective describing the substantial amount of the profits.
Las ganancias del proyecto fueron millonarias.
The project's profits were millions.
Here, 'millonarias' modifies 'donaciones', indicating the grand amount of money donated.