A tactical display was a graphic display designed to supply information to officers and crew of a starship or outpost, such as those used in Starfleet. The graphic usually displayed combat or other mission-oriented situations.
In 2285, Rear Admiral James T. Kirk called up a tactical display to gauge the relative positions of his flagship, the cadet training ship USS Enterprise, and enemy combatant USS Reliant, which had been commandeered by Augments led by Khan Noonien Singh. (Star Trek II: The Wrath of Khan)
In an alternate timeline created by the transposition of the starship USS Enterprise-C into 2366, a tactical situation monitor was posted in the USS Enterprise-D observation lounge. It displayed the arrangement of Klingon forces battling the Federation's forces and their relative positions across sectors of space, presumably in the same general area the two Enterprises were stationed. (TNG: "Yesterday's Enterprise")