Reflecting on the problem of relativism in which truth is defined by opinion, I tried to find the meanings of truth to clarify the concept. From the logical perspective, I know that truth is a measure of correspondence between two things. Also, the human knowledge starts with the basic understanding that a thing is or it is not, that there is being and not-being. I found the following meanings of truth: 

1. When what I know (concepts, ideas in the mind) corresponds to things (out in the world) my knowledge is measured by those things. This is speculative or formal truth. For example, saying that a triangle has three sides is true because it conforms to reality. Saying that the triangle has four sides is false. This is a correspondence of a thing to a thought. This truth is the mathematical and scientific truth based in measurable facts.
2. When the ideas in the mind are the cause of things, such as the work of an artist, there is a reverse correspondence in which we say that something is true. For example a design of a chair that functions as a chair is true because someone can actually seat on it. Or if I do what I intend to do. This is practical truth. This is the correspondence of thought to doing or making something.
3. The conformity of natural things to the divine intellect is transcendental truth. This is the ultimate truth of being. The correspondence of thing to being.
4. The conformity of our thought and our words is moral truth. This is telling the truth that is in the mind or voluntarily changing it and telling a lie. (On this, I think that moral truth can also refer to good vs. evil intentions?)

In conclusion I think that :

Metaphysical truth is in all things, transcendental being

Speculative truth is in our thoughts, the demonstrable things we know

Moral truth is in our words, the things we say

Practical truth is in our deeds, the things we do or make

Theological truth is from revelation

                                      When Our Lord Jesus said “I AM THE TRUTH,” he affirmed the correspondence between the perfect man and God. Thus, to contemplate Jesus is to know God.

So, I came with an interesting point of discussion: where is that “opinion” fits in this picture?  Is it a factual demonstrable thing? Is it an intentional doing? Is it a moral saying? Is it a natural being? Is it a revelation from God?Where does an opinion can get its corresponding material and formal relation to qualify as potential truth?