Tridextrous
The mists of time are starting to drift in, but I seem to remember that a general feeling at the time was that the T2 and T3 had more in common and the T1 should be its own fleet (if---if that was necessary at all). When "Tridextrosity" (??) was introduced, the view was that it had taken all those years for common sense to prevail.
Prober