The Pali word is "Samma." As for me and what I can say, I can't really answer this question 100%. Right Understanding has a definition in the scriptures, such as - to know the Four Noble Truths, to understand the Four Noble Truths, that is Right Understanding. Right intention or thought has its own definition, such as thoughts that are not cruel, thoughts of Compassion, etc. Right Speech has a definition - not to lie, not to talk about gossip and other things. There are these definitions within the scriptures.
So the word "Samma" in a definition has its answers, but let's go more than that, if we want to think of "Samma" as an ultimate word. Right understanding is truly the penetration of these Four Noble Truths, not just the knowledge of it. Right Intention is actually never having a thought of cruelty, harmfulness and so on. Yet we have to go on levels again, we're back to that aspect, that as much as you can develop Right Understanding, as to where your level is now.
If you understand the Four Noble Truths intellectually, okay. That's "right," compared to someone who doesn't know them at all. But you'd like to get them down into your heart, too. So you have got to develop them further. Intellectually you can understand that having speech that is full of gossip, bad language, lying and so on is wrong. That's Right understanding on a certain level, better than some people who don't even think it's wrong. But you'd like to make it on a deeper level, so you actually live that way too.