What does grand fatheded in mean in relationship to land?

If the term of being "Grandfathered in", in the term of land means that if there is a zoning changes or a territory change, this means the person's who owns the land, will not change at all. Their land will be the same, no additional zoning changes, etc.

Here is a picture  of the net. its 4 squares in a row diagonal and on the third draw one square aove and under