What is production code to you?

Been a Dev professionally for bout two years in multiple roles. But I am still uncertain what makes something "Production Grade". In the two companies and 3 roles I worked in (Product/Infra Support Engineer/DevOps, App Dev, Data Engg(Part of Managed Services Team)) I cannot see any "standard" metrics that are used to qualify that the code is production ready. For the different teams there were a lot that of difference in what can be considered production software.

Is there a set of industry standards? (apart from SLA, that you can take a look at the code base and decide that yeah this stuff is production grade??) Does passing all the tests and QA checks and getting UAT approval make it production grade?

I am really conflicted here because atleast in my experience what counts as production grade varies a lot by team/company. I am not talking about release ready builds or having a server launched with production args. I want to know how much individual responsibility in terms of the code we write ends up making a production codebase what it is.

And how do I know that it's enough given the deadline, priority and cost.