opening gun

The maid was in the kitchen out of ear shot, and Mrs. Hibberdell and Carlotta were in the library when the opening gun was fired.

The opening gun cleared my mind of all its anxieties and intensified its action.

How follow up the opening gun which he had fired at the expense of Gloster and the three miners?

The opening gun at Williamsport called his attention to a new danger.

He wondered if the widow was entering on a campaign to conquer her third, and had invited him to supper as an opening gun.