The difference between the Onto and on to?

Question

What is the difference between the on to and onto? In the Persian language both have the same meaning. Are they the same in English?

For example:

After reading the first part of the English book 1. go on to second part.

Or

After reading the first part of the English book 1. go onto second part.

Which one should be used when we talk about the next task that we would do?

Edit:

After reading the following web pages about the difference between the onto and on to, I come up with the answer.

Links:

• http://www.ldoceonline.com/dictionary/onto
• Link
• http://data.grammarbook.com/blog/definitions/on-to-vs-onto/
• http://writingexplained.org/onto-vs-on-to-difference

Here is the meaning:

• Onto: On top of, to a position on the surface of.
• On to: To move to the next level or to move forward to.

When to Use Onto

Onto is a preposition that means, on top of, to a position on, upon. Onto implies movement, so it has an adverbial flavor to it even though it is a preposition.

When to Use On to

Use on to, two words, when on is part of a verb phrase. In instances when on is part of the verb, it is acting as an adverb and to is the preposition, which takes an object.

Examples:

On to

Go on to the second page of the book if you're finished the current page.

Let’s move on to the next point.

I'll log on to the computer.

Onto

The cat jumped onto the yard.

He climbed onto the roof.

Let’s step onto the dance floor.

Answer 1

If in doubt you can write on to, which is always correct. Onto is an alternative spelling that can be used in some cases, though it is "still not wholly accepted" in British English, according to Oxford Dictionaries online.

The Oxford Dictionaries website defines "onto" as a variant form of "on to", and gives a usage note ( https://en.oxforddictionaries.com/definition/onto ) that reads:

The preposition onto written as one word (instead of on to) is recorded from the early 18th century and has been widely used ever since, but is still not wholly accepted as part of standard British English (unlike into, for example). Many style guides still advise writing it as two words, and that is the practice followed in this dictionary. However, onto is more or less the standard form in US English and in the specialized mathematics sense. Nevertheless, it is important to maintain a distinction between the preposition onto or on to and the use of the adverb on followed by the preposition to: she climbed on to (or onto) the roof but let's go on to (not onto) the next point

"Go on" is a phrasal verb meaning "proceed", hence we "go on to the next point" because we are proceeding to the next point.

Your examples with "on to" also involve phrases where verb+"on" constitutes a phrasal verb, such as "move on": "Let's move on to the next point". It is therefore preferable to keep the word "on" intact here and the word "to" separate.

Your examples with "onto" involve "onto" as a preposition, a word expressing the relationship between two things or movement between two things, often (but not always) physical objects: "He climbed onto the roof."

In your top example, "go on to the second part" would be preferable because "go on" is a phrasal verb, as discussed, where "on" is adverbial rather than prepositional. ( http://dictionary.cambridge.org/dictionary/english/go-on )