Simply stated, round the world tickets (or RTWs) bring travelers across both the Atlantic and Pacific Oceans. Multi-destination tickets (or “multi-stop” tickets, MSIs) on the other hand, don’t.
On an AirTreks around the world itinerary you can include any number of destinations in any order, including north and south legs and overland segments. That said, if you don’t take both a trans-Pacific and trans-Atlantic flight, you haven’t technically taken an around-the-world trip.
An around the world air route circumnavigates the globe, as illustrated in the map below.
A multi-destination or multi-stop air ticket is a trip that includes 3 or more flights to 2 or more world zones, regardless of which oceans you cross. See the map below for an example.
At least at AirTreks, these are technical terms with no bearing on how the airlines treat your ticket, how things work, or the overall cost. In our experience, sometimes RTW itineraries are cheaper, other times multi-stop trips are. Cost is directly correlated with the number of flights, not the terminology used.
When you tell your friends about your trip, call it whatever you like. Travel is vital. Crossing the oceans is optional.