What the heck is the difference between Dead End, No Exit, Not a Through Street, No Outlet, No Way Out?

Dear Fountain of Wisdom and Truth:

What the heck is the difference between Dead End, No Exit, Not a Through Street, No Outlet, No Way Out, and all the myriad ways to tell drivers that, barring death or UFO abductions, they're going to have to come back this way? Can't the engineers agree on how to convey the message? Are there factions, each espousing the merits of their particular word choice?

-- Pete Danes, on the road

Sign-writing isn't exactly the perfect creative outlet, and Caltrans seems to want to keep it that way. Dead End? No Exit? No Way Out? No way, they say. Any such signs you see on public streets must be very old. The traffic manual suggests two ways of telling people they're on the road to nowhere. "Not a Through Street" is what you might call a dead end -- one street, no cross streets, ending in a cul-de-sac. "No Outlet" means the road connects to one or more streets that wander around through the neighborhood, but to get back out, you have to exit the way you came in. Of course, no engineer is going to be locked up for going totally Burma-Shave one day and putting up a sign that says, "High-speed chase? Cops on your tail?/ Been drinkin' too much beer?/ Then don't turn down this road, my friend./ You'll end up right back here."