fandom_grammar . Answer: What is the difference between and correct usage of "onto" and "on to"?

callistosh65 asked: What is the difference between and correct usage of "on to" and "onto"?

With examples from Stargate SG-1 and X-Files

Is there a difference?

The words "onto" and "on to" are very similar. In fact, they even have the same letters in the same order, except for the space in the middle. The clincher is they even share the same pronunciation. They are one and the same, right?

Not quite.

According to Encarta's Dictionary, "onto" indicates position

"I know there are weapons in that box," Jack said, as he jumped onto the bed of the truck.

Scully was scared. She tried to fight back her terror as she stepped onto the dock. Something was out there - something big.

or being in a state of awareness

Mulder's excitement grew when he realized that he was onto something more interesting than Scully's skepticism.

Kawalsky pointed at Teal'c, his expression belligerent, as if to say, I'm onto you, Teal'c.

Moving "on to" greener pastures

When dividing the word up into two words, we are now using an adverb, "on", with a preposition, "to", which changes the meaning significantly. We are no longer thinking in terms of position or knowing what's going on. We've moved on, so to speak, and are now talking about going somewhere.

Scully ran on to the end of the road, calling for Mulder every step of the way.

Jack and Sam drove on to Washington in silence, both lost in their own thoughts.

A good way to determine which words to use: try to imagine the words "ahead" or "along" between the words. If it works, as it does in, "Mulder walked on [ahead] to the edge of the woods", keep the words separate.

A word of caution. There are a few instances when it would be correct to use either spelling, depending on the circumstances of the sentence, or how the words are used:

Jack flew the glider onto the runway. [on top of the runway]
Jack flew the glider on to the runway. [on toward the runway]

These instances are few and far between, but still a stickler to those who are not sure. Just remember that if you mean on top of or aware of something, use "onto". And if you want to indicate movement, use "on to".