Whatever the "technical" meaning of hit is, the meaning of the word to the general public is simply: a popular show, a "hot ticket". This meaning has been used not by just PR people but everybody, period. This term is applied as soon as a show opens, long before it makes a profit, and it may never make one, but it's still a hit.
And when a PR person uses the term, the public knows what it means, and it's not that the show turned a profit. They know it means they might have trouble getting a ticket. |