Webster’s Revised Unabridged Dictionary · 1913
Bracket
Brack′et, n. (Gunnery) A figure determined by firing a projectile beyond a target and another short of it, as a basis for ascertaining the proper elevation of the piece; — only used in the phrase, to establish a bracket. After the bracket is established shots are fired with intermediate elevations until the exact range is obtained. In the United States navy it is called fork.
Brack′et, v. t. (Gunnery) To shoot so as to establish a bracket for (an object).