What is the difference between one and one?

"One" replaces a countable noun in the singular, and "ones" replaces a countable noun in the plural. this/that + one, these/those + ones We can use one and ones with the demonstratives — this, these, that, those.

What does one-to-one mean?

One-to-one should be used when a discussion is held directly between two people. If you refer to The Cambridge Dictionary, you can see that one-on-one means “an activity involving two people talking directly, usually with one teaching or giving information to the other.”

What does one-on-one mean in a sentence?

We’ll start with the adjective “one-on-one.” We use this to talk about an activity that involves two people (though sometimes someone else can be present as well). I’ve got a one-on-one meeting with the boss next weekend. She has a one-on-one conversation with her mom. We are working with each other one-on-one. This is a one-on-one project.

Is one a number or a pronoun?

That "one" is not a number but a pronoun. @salierii - Are you encouraging management to revise the manual? The company hired 4 interns, but the fifth intern left. That is in keeping with your style guide and the meaning is much clearer. The "1" in your example refers to a person (the intern) not a number.