Why is Nibbana referred to as "The destination and the path leading to the destination"?

The dhammawiki page is correct follow to Pāli's structure.

Parāyanañca = Para (next) + Āyana (tourist destination; going).

The path leading to the destination = Magga.

Magga is leading to Nirodha (DukkhaNirodhaGāminiPaṭipadā).

So, Nibbana (Nirodha) is "The destination or object" of the path (Magga).

The talk The Essence of the Dhamma exlains good why the path is also regarded as "essence", leading to "essence". For only one derived at Nibbana, path can be abound to hold on, grasp, has become "his own".

Nivana and Nibbana are the same meaning words used for the same The Enlightenment in buddhism.

So Nivana word has the meaning of calm, quite, not hot - not cool (getting to normal state). This means the beings are not calm due to Raga, Dvesha, Moha. And we are hot => burning our minds with bad thoughts. When we get rid of these it's like we are getting in to the most calm position, which is Nivana

And when you take Nibbana This has another meaning but referring to the same state. If you know five aggregates and five aggregates of clinging latter is born as a result of chanda-raghaya(can also be explained as: attaching to things due to the lack of Vijja) on five aggregates. . Five aggregates has no issue but five aggregates of clinging which born due to the chnda-raghaya (on five aggregates) has issue.

'bana' means couple, and in couple there's some connection between two things (or persons). This connection is the cause which makes couple exist. So this chanda-ragaya is equivalent to the cause to exist the connection between Five-aggregates and Five-aggregates-of-clinging. Nib+bana means destroying the couple by removing the cause of the connection (chanda-raghaya) in between and that will result just existence of Five aggregates no more clinging parts.

So If I come back to your question, by doing all these (removing ragha,dvesha,moha or clinging aggregates) all it tries to see the world as it is. No attachments or no more getting cheated. This is called Nivana or Nibbana.

To explain you this more practical way,

Think what all of us are doing. We are running after what? We are running after happiness. Right?

But then why can't we just be happy by doing something and stop there. Why? Because we are not just looking for happiness we are looking for an ultimate happiness. That's why being happy doing one thing (achieving a goal, graduating, marrying , be a parent) doesn't make us stop. And we keep this doing until we die. (Even an old man tries to be happy by watching a game on TV).

So until we find the ultimate happiness we keep running. We never get tired (we do sometimes, but it just pauses our selves but not stops completely) why? because by doing something we actually feel the happiness. So we keep doing that. Imagine if you are finding a necklace in your cupboard (where you normally place it). After one hour still you haven't found the necklace, so you get everything out and continue the search, imagine even you make the cupboard in to pieces you couldn't find the necklace. What can be the reason for not finding the necklace there? Because Necklace is not there and you've been looking it in the wrong place. That's the only explanation for this right?

Same as Saṃsāra and Nibbana (or Nivana). The only place which you can be happy forever, or the only place which you can be ultimately satisfied is Nivana. That's why it's the destination. Once you are there there's nothing you want more because you are 1000% satisfied and happy. As a result you will stop suffering by looking happiness in the wrong places. And as a result you will not born again, which had been happening due to fact of looking happiness in the wrong places through out the Saṃsāra.