Well folks,
I found myself relating to the "tactical" knife I carried as a soldier. I read Lobo's post regarding the word 'tactical' liguistically, perhaps, being definitively usurped(?) as 'weapon' . I must say, after pondering a spell, I agree. I therefore deleted my initial reply and gained (brained) the knowledge;
If----- 'tactical' is subjective (it is) of 'tactic', then, a 'tactical' knife (or implement) would be then defined as any tool or device one would use, individual of thought, as being, the best tool/device/implement etc., to fold, spindle or mutilate accomplishing the task (ie: tactic)forthright beholden

.
For example, I might choose to use a wheeled cutter to section a pizza-pie, while, perhaps mossdancer (only as example, WB) might use a priceless Confederate States Cavalry Sword to accomplish this exactly same task.

Equally sized and palleteable.
Next, perhaps, Domino's will corner the market on Civil War swords???
IT COULD HAPPEN.

AAA--HHHEMMMM
Summarily:
I therefore submit: An individually defined "tactical" knife, as it must, encompasses ANY tool or method the tasked individual chooses/uses to complete the "tactic" at present hand.
My tactical knife was a SOG Trident (Bowie-type), still accomplishing a myriad of tasks/tactics. And, for which, I have and still would, trust my well-being; given a correct set of "tactics"
::blah:: ::blah:: ::blah::
Now, wasn't that easy????
LOVE the new emoticons Bry.
Take care all-,Glenn