How can we know the original meaning of a word with certainty? In a lot of discussions here in B.S.E, the topic of the exact meaning of some terms keeps recurring, and nobody seems to have the last word.

Words such as 'upapajjati', 'paccājāyati', 'abhinibbatti' are often translated as "rebirth", but for some, that doesn't seem to be the case. Or other terms as 'deva' or 'abhiñña' are understood as "god" and "psychic powers", respectively. Or even outside of Buddhist culture we find some terms such as 'prana', 'chakra', 'messiah', and so on.

How can we now the way people contemporary to the origin of such words understood those terms?

It is possible that they used those words to describe phenomena that we currently know by other more scientific terms?

For instance, in this entry (https://torvol.wordpress.com/2017/11/27/the-chakra-system-is-an-analogy-to-get-your-shit-together-not-spiritual-woo-woo/), this blogger assures that 'chakras' were the way used to talk about the regulation of emotions.

I hope you can understand my point.

Have a nice day, and thanks for your time!
How can we know the original meaning of a word with certainty?
Yes.
I'm sure there's a scholarly answer -- not this from me though.
Your mentioning &quot;chakras&quot; reminds of something similar, i.e. the &quot;chi&quot; that we're taught in Tai Chi -- which I learned from, was taught by, a Chinese master.
His English wasn't good, even with a translator I didn't ask complicated question, my own Chinese was non-existent though, I'm not complaining. Anyway part of what he'd do is describe the movement of chi -- especially the dan tien for example -- in reply, some students would say they could feel the chi, others not.
Based on a couple of answers (one on Skeptics.SE, another on MartialArts, which I won't reference) I've decided that &quot;chi&quot; doesn't exist as such -- not objectively measurable, and/or not separate from other things.
But ...
A lot of the preliminary work is to affect how you stand -- posture -- knees, hips, back, neck, and so on. We're told to &quot;stand straight&quot; ... and to, &quot;imagine there's a thread, from the sky to the top of your head, and that you're hanging from that thread -- so instead of being pressed and heavy and bent by gravity, you're being pulled and light-weight and hanging straight, with vertebrae aligned each above the other&quot;.
The exercise is effective, at least when you see it and follow along.
In reality, there is no such &quot;thread&quot;! :-) -- but I think it's a useful visualisation exercise. It helps you to stand straight ...

I guess I'm getting around to saying that &quot;meaning&quot; of a word is maybe difficult to ascertain.
One way, perhaps an important way, to know a word is by its effect -- what does it mean to you? What does it mean to other people? What is the effect of using the word?
In Tai Chi you can kind of judge how people practice --- how well (they practice), and how beneficial (their practice is).
Perhaps it's something similar in Buddhism -- i.e. you practice for a purpose, towards a purpose ... perhaps a purpose of your own ... or perhaps toward a goal and following a curriculum set by a teacher -- and the meaning of the words might be assessed by their effect, whether they help you to practice.
In a word like &quot;rebirth&quot; I think there are two important questions:

What does it originally mean?
What does it mean to me?

I see those as separate questions. I don't, can't, assume that I know the original meaning. I don't assume that what I understand is the real meaning.
It's partly a matter of ... is &quot;humility&quot; the right word? Knowing what you don't know? For example there's a bunch of stuff I know, that children don't -- how to drive a car, even how to bicycle. I imagine explaining that to a child, if they ask ... or &quot;How does a radio work?&quot; I could use words to explain, but would the words have the same meaning? If I say &quot;electromagnetic radiation&quot;, what's that to someone who hasn't studied it? What is it even to someone who has studied it?
Similarly I, being only very ... you know ... a student, I don't think I should assume that I'm able to understand the &quot;meaning&quot; even when it's explained.
But &quot;what does it originally mean?&quot; is an important question. I've posted questions, &quot;what does X mean?&quot;, so that people can explain that. And I don't think I should post to say &quot;It doesn't mean that&quot;. I don't want to misrepresent, I don't want to falsify the transmission.
It used to be that my knowledge of, access to Buddhism was very second-hand, third-hand, fourth-hand -- e.g. I'd read a book, explaining Buddhism, written by someone who had studied with people who had studied with other people -- and what's written in the book is, sort of, their opinion, their summary ... which is OK but, maybe not reliable, and maybe not much depth, the words are an easy explanation and superficial and there isn't much there, much substance, to study.
So I'm grateful to meet something like an original scripture and be able to study that, like, to be able to read what people are talking about.
But &quot;What does it mean to me?&quot; is an important question too, though. It's good to ask and good to be told, not enough though to be only able to repeat what you've been told. It's like, maybe I go to a Maths lecture -- and being able to repeat what was said, to memorise the lesson, that's one thing -- to use what's learned, to understand new (Maths) problems and to know how to solve them properly, that's another.
So I take an interest in both:

What is the, what is an, orthodox doctrine ... about the meaning? Can I understand it? Can I reference it? Can I, even, repeat it without distorting it?
Are there several orthodox doctrines? Not overly surprising if there were. Does a word have more than one meaning? Does the meaning depend on the context? Did it have several meanings in the original? If several people understood it, did it have several meanings then? Was it intended for several people, perhaps with different understandings?

What does it mean to me? How can I use that doctrine? Can I use it? If I only understand it partially, is there a part of it I can use?


I guess a final question might be, how do I manage a part doctrine that I don't understand? I guess I &quot;neither approve nor disapprove&quot; but &quot;put it aside&quot;. There's a lot of knowledge in the world -- practical and theoretical knowledge, science, arts, know-how -- the fact that I don't know something or don't understand it doesn't mean it's untrue, doesn't mean it's impractical, or badly taught.
nobody seems to have the last word
No.
This is meant to be a Q+A site, is one thing, so in theory everybody &quot;has the last word&quot;. You ask a question, people answer, and you select from among the answers to build your own understanding. There may be some good answers, maybe some less good, you don't always have to have the last word, or do you.
One of the stack exchange guidelines I read was that answers should be &quot;backed up&quot; or &quot;based on&quot; something, either:

A reference
Something you have experience personally

I think that's quite a good guideline for this site and this topic (i.e. Buddhism) too.
If I answer I like to ...

provide a reference
and/or, explain from my personal experience

... and by doing that I hope to be not misleading.
(Not that all answers require references on this site ... e.g. with many people/users/readers are familiar with the same doctrines and it's often enough and more convenient to explain a doctrine without references).

Perhaps I should, I don't know whether I should, mention one more thing -- i.e. that you might want to know, be certain of, your own understanding -- perhaps to ask, &quot;what do I understand?&quot;, to avoid confusion.
For me personally I think it's right to, I think we're taught to, disentangle from a &quot;thicket of views&quot;, perhaps recognise and avoid &quot;a thicket&quot; from a distance, maybe &quot;know your own mind&quot; for what that's worth as they in English, and maybe no &quot;It means this! No, it means that!&quot; like the sectarians.