International Institute of Cricket Umpiring & Scoring
Third umpire, upstairs

The off-field umpire who, with the aid of television replays, assists the on-field umpire to make a decision.
Not all decisions can be made with the assistance of the third umpire but the most common are Run out, Stumped, some catches and close boundaries. The on-field umpire is said to 'go upstairs'.
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