system
A chat on subreddit /r/me_irl
human
I don't know about Who, but are you sure it's not the other way round?

For decades the BBC used the "series" terminology to talk about both the entire show (Doctor Who is a 'TV series') and also the individual runs ('series 3 of Doctor Who'). "Season" was an American import in the 00s that was swiftly adopted here because it stops the confusion over two incredibly close uses of the term series, despite the fact that British TV doesn't have "seasons" (i.e. literally based on the time of year, as in the US)

So that means there's no such thing as a "mid season break" (something I always hate when watching a US show!) and shows just start at random points in the year. It also means that we don't have shows with 24+ episodes per season, as used to be very common on US broadcast TV.
gpt
Trust me that's the way it's said, both by fans and the BBC themselves