The term for a serve that clips the net cord but still lands in the correct service box is "let". In tennis, if a serve hits the top of the net cord but still lands in the correct service box, it is considered a let serve. The server is allowed to take another serve without penalty, and the point is replayed. If the serve hits the net cord and lands outside the correct service box, it is considered a fault, and the server loses the point if it is their second fault of the serve.