Is there a solid definition for these terms?
I consider armed to mean a person has a weapon.
Well armed to mean a person has a quality weapon and the knowledge of how to use it.
I don't know what I would consider haevily armed.
Just curious.

Well the media has a big wheel they spin, and whatever it lands on you have.

Some guy holds up a 7-11.
man has a 1911 pistol.He has two extra magazines for it.
Here's media spin.

"Crazed heavily armed gunman,toting a high-powered military-style hand-gun robbed a 7-11 today"
having extra magazines for ANY weapon means "heavily armed"
a .38 with an extra load on a speed-loader is heavily armed.

Armed-Has a firearm.

Well Armed-Has a firearm, the know how to use it and the proper amount and caliber of ammo.

Heavily Armed-Has a firearm, not only the know how but some skill to use it, an amount of ammo that is sufficient to do the task at hand 100 times over, a back up firearms of some sort within easy reach, a knife if all else fails, and is wearing clean underwear. [BD]

In our terms I think you already answered the first two. Someone can be "armed" with any gun (or knife for that matter) but if they do not know how to use it there is really little point.
Well armed, to me, means someone carrying or holding a weapon and the possess the knowledge to use that weapon effectively.
Heavily armed, again to me, means someone that arms themselves more than perhaps they need. I, and I'm sure several here, would fall into that catagory. (I carry a six inch Smith model 29 as a primary and a custom snubby model 29 as a back up. Depending on where I'm going I may also drop my ADC .44 mag derringer in my pocket in addition to the above. And, of course, I always carry spare ammo.)

But if you are referring to the medias definition all bets are off. They may report someone with an auto carrying ten rounds as heavily armed. To them the terms are used to create hysteria among the viewer/reader to increase ratings and demonize guns. But you have to bear in mind these are the same people that bring us the "assault weapon" and the automic revolver. (No, we are not talking the Metba(sp?))

The terms are all subjective, based on the word user's point of view.

1. If the user has a gun/ammo, he is armed.
2. If the user's friends have the same as or less guns/ammo than what the user has, they are armed.
3. If the user's friends have more/better guns/ammo than the user does, they are well armed.
4. If an enemy of the user has anything at all, including a pencil, no matter what the user and his friends have, the enemy is heavily armed.

Don't forget, whatever the Criminal has as a weapon was bought with the "Gunshow loophole".

I kinda figured it was a point of view kinda thing, but I was curious so I had to ask.
I generally cosider myself well armed, but have been asked why I am so heavily armed.
As a general rule, I have a .45 on my person, a 9mm within reach, and an Ar or mini 14 in the vehicle.
Guess it is a good thing I live a long ways from anywhere.