Looking to search for the number of times, one of a selection of words appears?

I have an example whereby I want to search how often one of the following in a vector of strings appears in a corpus/DataTermMatrix e.g I want to search how often at least one of the following appear ("sun", "moon", "stars") per entry and also how many times it appears in aggregate, i.e count two if two words from the vector appear?

Many kind thanks lovely helpful people of the internet.