cornerstone

noun

cor·​ner·​stone ˈkȯr-nər-ˌstōn 

1

: a stone forming a part of a corner or angle in a wall

specifically : such a stone laid at a formal ceremony

2

: a basic element : foundation

a cornerstone of foreign policy

Synonyms of cornerstone

• basis
• foundation
• bedrock

Examples of cornerstone in a Sentence

Officials held a ceremony to lay the cornerstone for a new library.

Trust is the cornerstone of their relationship.

Recent Examples on the Web

Meanwhile, Punk, now positioned as a cornerstone of SmackDown, is expected to move on to new challengers as the brand builds around its reigning champion. — Blake Oestriecher, Forbes.com, 2 Aug. 2026

Baresi was the cornerstone of the Milan and Italy defenses for nearly two decades, captaining the Serie A club during the most successful period in their history and earning 81 caps for the national team. — CNN Money, 31 July 2026

Coming off a career year with 13 sacks in 2025 and 26 over three seasons, Tuipulotu has become a cornerstone of Jim Harbaugh’s Chargers defense. — Joaquin Ruiz, Los Angeles Times, 30 July 2026

Olave will remain a cornerstone piece for the franchise alongside new starting quarterback Tyler Shough, who was drafted in the second round in 2025. — Scott Thompson, FOXNews.com, 30 July 2026

Word History

First Known Use

13th century, in the meaning defined at sense 1

Rhymes for cornerstone

• acetone
• anglophone
• baritone
• bourguignon
• buspirone
• chaperon
• chaperone
• cobblestone
• collarbone
• cortisone
• dictaphone
• dithizone

Kids Definition

cornerstone

noun

cor·​ner·​stone ˈkȯr-nər-ˌstōn 

1

: a stone forming part of a corner in a wall

2

: something of basic importance

the cornerstone of our foreign policy