The Segway logo is known as the Flyguy and traces its name back to the time when the Segway Personal Transporter (PT) - or Human Transporter (HT) back then - was going to be called the Flywheel. The character evolved from a backwards capital letter F. Flywheel was Dean Kamen's preferred name for his invention. There were quite a few other names considered, with Acros being both the primary contender as well as the company's stealth name. Presumably, Acros was derived from a shortened version of the word across. It has been reported that Kamen never liked Acros, saying that it sounded somehow generic...like the name of a Japanese car. According to one source, here is how the name Segway came to be chosen:

It occurred in the late summer of 2001, just a few weeks before we needed to lock in on a name for the company and product. Here were the other names considered: - Acros (the company's stealth name) - Citywave - Crosswing - Flywheel - Glideka - Glidewalk - Glidewave - Landwing - LinkIt - Relay - Transfer - Transglide - Wingstep When Gary Bridge came on-board in August 2001, he immediately recognized that "Flywheel," as both a company or a product name, would not market well (had nothing to do with domain name unavailability (as the Project Ginger book claims), as Segway.com was not available either until the right price tag was attached to it). He pushed the marketing team and Dean to find another name. By Sept. 2001, the name Segway was making the rounds and was presented in the Oct 2001 board meeting as the name we should use to go to market. It received board approval at that time. Internally, many in the company felt Flywheel was the better name because the name "Segway" had such a short time from when it originated to when it was accepted. Whereas Flywheel had been the default public name employees had heard up until Sept. 2001. Then within about a months' time, it was gone and Segway was "it."

One concern with the name Flywheel was that to many people it implies something that is flying along, out of control. Ironically - and as engineers know - the purpose of a flywheel is to smooth out power impulses by providing a larger source of angular momentum. In other words, it is a stabilizing device. No wonder it was Dean Kamen's first choice. And anyone who has been to his house in New Hampshire and walked in through the front door will know he loves BIG flywheels (read Project Ginger to lean more). As to where the word Segway itself came from, Dean Kamen has told the story on a number of occasions. Here are two recollections by Segway PT owners:

The way I remember Dean Kamen relating the story of how Segway got its name--both at dinner one evening in New Hampshire and at SegFest2003 in Chicago--goes something like this ... Somewhere in the 2000-2002 timeframe (I don't know the exact year, but I'd guess sometime in 2001) Dean had traded his Cessna Citation business jet for a new Raytheon Premier. In his simulator training for learning to fly his new plane he was required to do a rapid descent from something like 30,000 feet to 8,000 feet ... simulating an eUPDATEncy decompression event. Guiding the plane down from one "state" to another with all sorts of alarms going off in the cockpit, the name suddenly hit him. Segue ... Segway.

And from another person at SegFest 2003:

We had a conversation with Dean in the bar afterwards and I can tell you that I got it straight from the master's mouth. Dean was taking his recurrent flight training in a flight sim in Kansas City and he was exhausted from a week of doing all those Dean things and flying about the country in his plane. Time was running out to complete this training so that he could continune to fly single pilot in this particular aircraft as a result he was under the gun to complete this task in a short time. He had been looking for unique name that would translate well and not mean cockroach or a similar undesirable name in another language. They had considered "Flywheel" but there were some copyright issues with that one. At any rate he had been racking his brain looking for the right fit and during that session in the flight sim he was forced to make an eUPDATEncy descent from 30,000 feet down to 8000 feet as a simulated pressurization failure. This had to be done within about a minute if I remember correctly and during this simulated descent the thought occured to him that his was making a transition, or a segue, from one flight level to another. Then he thought highway, driveway, SEGWAY. It was easy to spell unlike the original segue and a name that Americans could pronounce, and get right the first time from the spelling, now the only remaining obstacle was if some other entity had copyrighted it. He immediately called up counsel but couldn't get anyone on the phone...he had forgotten that it was a Sunday and no one was in the office. As luck would have it Segway was unencumbered and the rest is history!

And finally, a description of the root word segue:

My understanding it was a play on the word "segue" (but pronounced "seg-way") which, in recorded music, is a seamless transition between one song and another. In journalism, a segue is a method of smoothly transitioning from one topic to another. A segue allows the host or writer to naturally proceed to another topic without jarring the audience. A good segue makes the subject change seem like a natural extension of the discussion.The word has a variety of similar meanings and I read somehwere that Dean believed it epitomised the vision he had for this device, i.e. being a smooth transition beteen ordinary walking and mechanical transport.