A tool or device used to bracket something; or a person who brackets; or a mounting device in construction or carpentry.
From 'bracket' + '-er' (agent noun suffix, one who does or makes something), creating a term for the tool or person involved in bracketing.
In carpentry and construction, a 'bracker' is a practical tool—the '-er' suffix is English's favorite way of turning verbs into tools or people who do the action!
Complete word intelligence in one call. Free tier — 50 lookups/day.