Okay, it's like this. From the trunk all the way out to the branch tips. So when you diagram it, it makes a circle on the soil surface. Thus all the area on the soil surface fromthe etrunk to the branch tips is "within the dripline."

Thus, both labels are correct.

All that said, if the soil is decent quality, ornamental trees don't need any fertilizer. Just makes them grow more so that the gardener must prune more.

Unfortunately, in hands of the misguided, pruning is, instead, hacking back -- not a good thing.

Thanks jean001a
I appreciate the explanations. Let me add that, when I talked with each company rep, I had them walk me through an example. I believe the example I used was a tree where "the distance from the trunk to the outermost branch was 3' and, therefore, the canopy (from outer edge on one side to outer edge on the opposite side) was 6' ". The first rep said that, in this example, the branch spread is 3', while his counterpart said the branch spread was 6'.
Funny how trends evolve. Many, many years ago, everyone from the farmer to the occasional gardener swore by the absolute need for fertilizer. According to them, without fertilizer, plants would be puny if they lived at all. Then came a period, or so I read, that over-fertilizing was more harmful to the plant than under-fertilizing. More recently, most of the comments I've read, both on the Garden Web and elsewhere, repeat what you said: most woody plants need no fertilizing unless they're showing specific symptoms, in which case you add only the elements necessary to address the problem. (Wouldn't you know it ...every time I visit the garden centers around here, they praise to high heavens the powers of the fertilizers!) :0) And the more I hear and read, I'm being persuaded to abandon the "fertilizer for all" bandwagon.
And thanks for the tip on pruning. My uncle taught me some years back that, based on his experience, pruning could be counter-productive: it increased the growth of a tree. My only efforts at pruning have been to remove dead branches and branches that rub against each other. I do plan, however, to do some very light pruning of some new crape myrtles. In an effort to have them to grow in a tree form, as opposed to a shrub, I'll remove a few of the lowest branches each year. There are multiple examples of what I understand is called "crape murder" around here... ugly, ugly, ugly.
Again, I'm obliged for your help and advice.
gary