When I look at my flight itinerary, it says that the flight includes a technical stop.
What does that mean compared to a layover?
Usually it's a refuelling stop, and you just sit on the plane. You don't go into the terminal, the plane isn't cleaned, and you're soon on your way again. As an added bonus, the airline isn't charged for using the terminal, so the tickets are sometimes cheaper as a result.
After some reading of forums, the whole leaving the plane thing is possible depending on airline or terminal.
In addition, another type of technical stop is where for example you have a fuel leak or engine failure and have to land to get it sorted. However these are usually (obviously) unplanned, so the fact it's on your itinerary means it's likely the former (fuel stop).
A technical stop is for the benefit of the PLANE. That is for refueling, inspection, repairs, etc.
It is not a stop for the benefit of the passengers. That is, it is not for loading or unloading passengers, and it could be in some out of the way place.
The plane has "technically" stopped. (In U.S. car traffic terminology, it might be referred to as "standing.") But it has not made a stop for the usual purposes.
As others have mentioned, it can be a brief stop for fuel. In addition, the plane may change crews and take on meals. In my experience, the passengers will be often asked to leave the plane for about 30 minutes or an hour, spending some time at the terminal and having an opportunity to do a little shopping and have a drink at a bar airside.
A technical stop might be primarily for fuel or crew scheduling. Some routes may have technical stops depending on weather, for example, LAX-HKG when operated by a 747 often makes a technical stop for fuel during the winter (when the headwinds are stronger in that direction) but not in summer. It's rare for such weather-dependent stops to be published in the itinerary, since they may not be decided until shortly before departure.