my house is old 14th/15th century and was a as they call it in french ( un forteresse ) there is even a point in the house that you can put out a gun to defend against attackers , so i will be safe if you come to attack me , i will pm you a photo ,only because i know you are into old things like my self,(or think grumpy and others will get mils out of that one ) as i don't want to be said again that i am trying to push myself when i am only trying to answer you , the field ( domain) has nothing to do with my farm as it is on a second farm that we have 15km away and farmed with this farm ,had being before we came , and there is not house or buildings , but near by there is 2 small chàteau so it might have something to do with one of them ,I would hazard a guess, that your farmhouse is very old, and at some point probably before 1800 was the centre of a small estate.
Most of the land would probably have rented out and "le domain" was the only piece that the landowner kept in hand.
In England particularly, and in Wales to some extent, it equates to the Home Farm of landed estates in the 19th Century Onwards.