Single family residence or farm - is an American zoning term, meant to describe private homes.
The “or farm” part is so it encompasses the house on a farm. Houses have different insurance processes than other structures. And if for sale, houses are priced differently than, say, a commercial building of the same size. Also, private homes have special laws around them, for privacy.
If you’re working in one of these industries, you see the “or farm” in context, and it makes perfect sense. But Niantic published it to reviewers without the context.
IOW: A trail sign, produce stand, corn maze, etc on farm property - are fine locations for wayspots. Just not the farm house or yard.