<p><strong>Noun</strong></p><ul><li>a stone uniting two masonry walls at an intersection</li><li>a stone representing the nominal starting place in the construction of a monumental building, usually carved with the date and laid with appropriate ceremonies</li><li>something that is essential, indispensable, or basic: The cornerstone of democratic government is a free press</li><li>the chief foundation on which something is constructed or developed: The cornerstone of his argument was that all people are created equal</li></ul>