Definition

Noun: 1. A stone at the outer corner of two intersecting masonry walls: A foundational stone that forms the corner of a building's structure. 2. A stone in the exterior of a large and important building; usually carved with a date and laid with appropriate ceremonies: A ceremonial stone, often inscribed, placed at a formal building event to signify its commencement. 3. The fundamental assumptions from which something is begun or developed or calculated or explained: The most essential part or basis upon which something is built or depends.

Usage Examples

• Literal (Building Stone):
  • The architect inspected the cornerstone to ensure the walls were aligned correctly.
  • The ceremony for laying the cornerstone of the new library will be held next week.
• Figurative (Fundamental Part):
  • Trust is the cornerstone of any strong relationship.
  • This scientific discovery became the cornerstone of modern physics.

Advanced Usage

• "To be/lay/serve as the cornerstone of (something)": To be the most important, fundamental element that supports something else.
  • Free speech is the cornerstone of a democratic society.
  • The new evidence laid the cornerstone for a revised theory.

Variants and Related Words

• Cornerstone is a compound noun formed from "corner" and "stone." It does not have direct verb or adjective forms.
• Foundation stone: A very close synonym, especially for the literal and ceremonial meanings.

Synonyms

• Basis: The underlying support or foundation.
• Bedrock: The solid foundation or fundamental principle.
• Foundation: The base upon which something stands or is supported.
• Keystone: The central, most important part of an idea or system (architecturally, the central stone at the top of an arch).

Related Phrases

• To rest on a cornerstone: To be supported by a fundamental principle.
  • The entire legal argument rested on the cornerstone of precedent.

Related Idioms

• "The cornerstone of [something]": This is the most common idiomatic usage, directly employing the word's figurative meaning to indicate indispensability.
  • Regular practice is the cornerstone of musical mastery.

Noun

1. a stone at the outer corner of two intersecting masonry walls
2. a stone in the exterior of a large and important building; usually carved with a date and laid with appropriate ceremonies
3. the fundamental assumptions from which something is begun or developed or calculated or explained
   • the whole argument rested on a basis of conjecture