In English common law, real property is distinguished from “chattel” (aka personal property, movable property in various jurisdictions.) Based on my reading of the Wikipedia page of it when you sell your farm, you leave the building and land there which becomes the new owner’s, but you bring along your cattle with you which remains yours. This distinction between real property and other property persists to today. In Canada (with some possible exceptions in Quebec and special areas), real property consists of land, buildings on the land, and anything permanently affixed to them. Tangible personal peroperty consists of things, goods, material, livestock and more. Intangible personal property are things that don’t have a physical manifestation but you can still own and sell, such as a patent or license.

That’s a whole discussion, but the gist is the real part of real estate comes from this. The French immobilier and the Japanese 不動産 discuss real estate directly as a trade/industry dealing with un-movable things.