Knowing how to ask a category of question is often more important than knowing the answer to one iteration of a question.
Yahoo is not the originating source of any equity trade/quote data, as far as I know.
That means Yahoo has zero say in defining any of the fields in equities trade history data series.
The originating source for a data series should hopefully be indicated somewhere accessible from the platform which is resdistributing it.
When I lookup AAPL on finance.yahoo.com, I see that instrument code has its data sourced from NasdaqGS.
When I lookup DOCN on finance.yahoo.com, I see that instrument code has its data sourced from NYSE.
You must then go to each exchange which is the source of each data series to see how they define those fields.
If you are gonna be in this game, that is something you are gonna have to learn how to do,
unless you can afford a mid to higher tier market data terminal that does some of that legwork for you,
along with offering multiple sources for a given instrument code,
and sometimes offering a synthetic data series aggregating values from multiple different sources.
Left as an exercise for you is to search the web site for the data source cited by Yahoo for the instrument code (ticker symbol) you are viewing.
This is a skill you need to learn and it is time for you to start putting in some sweat equity towards your tuition.