Michael D. Daudt Eminent Domain Law Blog on Lawyers.com

Eminent domain refers to the governments power to appropriate private property with or without the owners consent - providing there is a fair market value compensation to the owner. The act of taking property under eminent domain in known as condemnation. Most people get this condemnation confused with a building being "condemned" for being unsafe structurally. The government may exercise eminent domain over private property whether it is land or food or material that can be used during war time and so forth.

The examples of eminent domain / condemnation that most people remember is in the history of how the railroad got built. The railroad was considered of vital importance to the country and all the land the tracks went through was condemned and sold to the railroad companies. The same practice is used whenever a new road is built.