When people talk about "private" courses over here, they're generally referring to exclusive clubs/courses that do not allow outside play. Where only members and their guests are allowed. Most even limit the number of times an individual guest may be invited each year.
Because of the exclusivity, the cost of such a club is generally much more than playing ala carte golf elsewhere. A completely different animal than a daily fee course that offers a discounted "membership" to attract those that play enough to make it mutually beneficial to both the course and the avid golfer.
Thanks for the explanation. I understand the distinction, but I'm not talking about "daily fee courses". Most clubs in the UK are private and owned by the membership, and in a position, if they wanted to, to restrict playing to only members and their guests. But very few don't accept visitors, largely because they want the income, but partly because it is mutually beneficial. Lots of people want to play a variety of courses occasionally, and clubs allowing visitors makes that easy to achieve. The very few that don't allow this tend to be extremely expensive and exclusive.
Of course, there are restrictions. My own club will only allow visitors to play on weekdays or late in the day at the weekends (in the unlikely event they can get a tee-time on those days), and a lot of tee times are reserved for members-only.
Just a different tradition, I guess.