See this thread
https://forum.safeguard.co.nz/discussion/comment/924

I'm interested in what you are going to do with the definition once you have it. As I usually see the term HiPo defined for the purpose of what is going to be seriously investigated - i.e. if it's HiPo it's ICAM. if this is the case I would challenge to think from the other direction - define (with the company) what you will put the effort into investigating, and what falls under the heading of stuff not to sweat.

As for directly answering the question - I worked for a company where HiPo was roughly defined as LTI or above injury or a non-injury with a potential risk rating of high or extreme.

Cheers Craig and MattD2.
Recently our board are asking more visibility on our critical risk and part of this have asked for reports on all High Potential events. This has jumped though a few people to be requested of me, so to ensure accurate reporting, I want us to define high potential so we are talking about the same things.

The tough thing with a definition like HiPo is (as you've found) there is no single global definition for the term - usually it is company specific, and at best maybe a national industry term that most of the big players use. This is fine if it is purely being used internally, but will soon turn into chaos if the board starts to compare across other companies - I think the biggest trouble of trying to use a "standard" industry definition for a board is you will inevitably end up with multiple opinions on what the "actual" right definition is based on their past experience or other boards they sit on (and if we are talking independent directors then this is something the business is actually paying them for - clearer outwards perspective instead of executive directors who can tend towards an inward focus).

Recently our board are asking more visibility on our critical risk... — Mark Kenny-Beveridge

The fact that the board has started this by asking for more visibility on critical risk may in fact give you something to play with... if they are up for it! If instead going with the typical approach of defining HiPo based on the actual or potential outcome, maybe consider if you could instead define it by what went wrong... by using your critical risks / critical risk controls as the triage metrics you can capture a clearer picture of where, when and how your risk management process broke down in areas of high risk, which should also lead to better detailing of what needs/could be done to strengthen that risk management processes (both in terms of actions, and clear connectives from incident to action for the board to support).

Just one other issue I have seen in the past where the definition of HiPo is based on the actual/potential outcome is the reasonable common occurrence of events that do not end up on the intuitive side of the line - someone slips over and rolls their ankle ending up with a few days off to recover on crutches being considered a HiPo (temporary disability), where a chain snapping during a heavy lift is not just because it was only 500mm off the floor at the time it happened...

Source: Dr Dominic Cooper

IMO, this sort of definition should be company-specific. It all comes down to the company's risk appetite.
What's an acceptable risk for the Board? What do they deme to be an acceptable level of total risk?

Incidents don't only have personal outcomes, there are financial, reputational, etc outcomes as well.