*shrug* to know the original meaning, you'd have to ask the Japanese creators of the video games...I know in Japan they're Rocketto-Dan, but I'm guessing that still means "Team Rocket"...
Let us look at the actual team rocket motto (not the one used by Jessie and James) to see if there are any hints:
To infect the world with devastation
To blight all peoples in every nation
To denounce the goodness of truth and love
To extend our wrath to the stars above
(names of members saying motto announced, for example: Cassidy! Butch!)
We're Team Rocket, circling earth all day and night
Surrender to us now or you'll surely lose the fight
In this case, it would seem that they have so much desire to control the world they speak of themselves as above the world, or better than the world, and Team Rocket would signify that they are moving themselves to positions of higher and higher importance, and eventually to the levels of rulers of the world.
Let's then take a look at the Japanese Team Rocket motto to see what the original makers of the show intended:
Musashi: If you require to know who we are...
Kojiro: ...listen to us guys
Musashi: To guard against universal destruction
Kojiro: To keep the universal peace
Musashi: We carry out an evil of love and truth
Kojiro: We are loving and charming villians
Musashi: Jesse!
Kojiro: James!
Musashi: We Rocket dan travel any stars in the Galaxy and...
Kojiro: A white hall- A white future is waiting for us
Nysuuu: Right!
In this case, it shows a whole different side to TR. In Japan, it seems that the organization desires to keep order in the world instead of taking it over simply for power-related reasons...I think, from this, that in Japan their desire was to take over the world to keep order. Interesting, eh?