A Starfleet Tactical Wing is a military unit consisting of anywhere between fifteen Starfleet starship to forty vessels. A tactical wing is a step down in the organisational structure of a fleet and above that of a wing.
Tactical wings are usually commanded by a captain, though it is not unheard of for a Rear or Vice Admiral to be placed in command of a tactical wing. (Last Unicorn RPG: The Dominion War Sourcebook: The Fires of Armageddon)
The Breen also use tactical wings called tilga'kars. The size of a tilga'kar depends on the size of the brot'kar they are part of, with large brot'kars fielding larger tilga'kars. (The Dominion War Sourcebook: The Fires of Armageddon)