What exactly is "Nirodha" in the 4 Noble Truths?

The cessation of suffering (Nirodha) has at least two meanings or notions"

1 The state of being - Nirvana.

2. The desired state - dirty air to a more desirable state - clean air

I guess the Buddha was referring to the former, that is, the cessation of Dukkha.

In the cosmological discussion, Buddhist scholars sometimes ponder upon the two states - Nirodha and Nibbana.

The Four Noble Truths

Statue of Buddha, 1st-2nd century CE, Afghanistan ©

"I teach suffering, its origin, cessation and path. That's all I teach", declared the Buddha 2500 years ago.

The Four Noble Truths contain the essence of the Buddha's teachings. It was these four principles that the Buddha came to understand during his meditation under the bodhi tree.

1. The truth of suffering (Dukkha)
2. The truth of the origin of suffering (Samudāya)
3. The truth of the cessation of suffering (Nirodha)
4. The truth of the path to the cessation of suffering (Magga
   
   
   
   Source: BBC (2009, Nov 17). The Four Noble Truths. Available online at https://www.bbc.co.uk/religion/religions/buddhism/beliefs/fournobletruths_1.shtml