Tactical means for war. Strider knives are tactical knives, as they are designed for war conditions. Thick but sharp, tough, easy to reach, stay in your hand when the $hit hits the fan, and so on. A slip joint filder with 1" blades are not war knives. Yeah they have some utility value for the soldier, but they don't cover most of the tasks a soldier will need his or her knife for. As mentioned, prying open ammo cans, building bashas, rotating the barrels of a minigun to clear a jam (done with a Strider once), using to stab a bad guy who is trying to take your firearm for you and similar tasks are tactical tasks.
So, "tactical" tasks are a subset of the general tasks we call "utility" tasks. Utility tasks include things like opening the mail, skinning a deer and prying open ammo crates.
Now, here's where things get confusing. I think that the knife companies and mags and such generally lump things into fighting tasks or utility tasks. Knives that are good at both are called fighting/utility knives! I carry an AFCK right now and I would call it a fighting/utility knife. It is made of materials and has a geometry that lends itself well to my every day chores. Also, this knife is long enough and strong enough and sharp enough to save my ass if things ever came down to that. I also carry a "utility" knife. It is a SAK type knife on my keychain. This knife would suit fighting tasks poorly, and I won't pry with it other than to get a staple out of some paper. But this knife opens my mail just fine, opens packages, and so on.
Yes, there are some knives out there that have the funky names and the funky designs that aren't good at fighting or other utility tasks! Here's where you the consumer have to be vigilant. Whenever buying a knife, first of all start with a list of what you want the knife to do. That list is a list of utility tasks you need to complete with your knife. Now, get a knife that will do all you want it to do. And be aware of others just cashing in on the "tactical" craze.
So, all tasks are utility tasks. Tactical tasks are utiltiy tasks that the soldier or police officer will run into. Whatever knife you get, make sure it will do all of the utility tasks you will ask of it. And stay away from those Rambotron Death Maker Life taker Surgical Stainless Steel Slip Joint Master Killer knives if you need to defend your life or pry open an ammo crate! Or even to make a cheese sandwich for that matter...