Correct spelling, explanation: both discussion on and discussion about are commonly used, but they may be preferred in different contexts. Discussion about is more widely used and generally considered more versatile. It is often used when referring to the topic or subject matter of the discussion. Discussion on is also used, but it might be more specific and less commonly used than discussion about. It is often used when referring to the act or focus of the discussion rather than the topic itself. In many cases, the choice between discussion on and discussion about depends on personal preference, context, and the specific nuances of the topic being discussed.

Definition of discussion on:
Phrase, refers to the act or process of talking about a particular topic, issue, or subject matter
The panel led a thought-provoking discussion on the impact of social media on mental health.
The students engaged in a lively discussion on the merits of renewable energy sources.

Collocations with discussion on:
Some of the most commonly used collocations include:
1. Discussion on climate change: conversations focusing on the phenomenon of climate change, its causes, impacts, and potential solutions.
There was a productive discussion on climate change at the environmental conference.
2. Discussion on human rights: conversations centered around the protection and promotion of fundamental human rights.
The United Nations held a discussion on human rights violations in conflict zones.
3. Discussion on education reform: dialogues concerning changes or improvements in educational systems, policies, or practices.
The committee scheduled a discussion on education reform to address declining literacy rates.
4. Discussion on healthcare policy: conversations focusing on policies related to healthcare delivery, insurance, access, and affordability.
The government initiated a public discussion on healthcare policy reform to address rising costs.

Correct spelling, explanation: the choice between discussion about and discussion on can sometimes depend on little nuances in meaning and context. Use discussion about when you want to emphasize the topic or subject matter of the conversation. Use discussion on when you want to emphasize the activity or focus of the conversation rather than the specific topic. However, it’s essential to note that the distinction between the two is subtle, and they are often used interchangeably in many contexts. Both phrases are generally understood, so the choice between them often comes down to personal preference or style rather than strict grammatical rules.