Haircut or a Trim?

You've heard the phrase before, you may have even said yourself. "Oh, I just need a trim." I'm thinking it should be simple enough, until upon further questioning I find that its going to be a more involved and/or time consuming than I expected. I've noticed that some salons have different prices for a haircut or a trim and others only have a haircut price (for this reason, I'm assuming). Being that I'm a guy and my hair is fairly short, I alway ask for a haircut since the stylist is basically going to have to do the haircut all over again, but I've seen people with short hair say they "just need a trim." So here's the point, I would like to put a question out there to all of you: "What, in your mind, is the difference between a haircut and a trim?" This would help me understand the mind of the client since I was under the impression that a trim is what Pivot Point calls "Solid Form" and Vidal Sassoon calls "Single Length." I look forward to your opinions, impressions and so forth and to further clarify my point I'll show you want I believe can be "trimmed" and what would be a full-on haircut. First, the trim:

Second, the full-on haircut: