keystone
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Southern red wood ants are considered a keystone species, meaning they play an important role in supporting healthy ecosystems.
From BBC ● Jun. 28, 2026
She pointed to the 1967 Outer Space Treaty, a keystone document on international space law that President Lyndon Johnson signed onto.
From Salon ● Apr. 9, 2026
On immigration, the keystone of Trump’s policy platform, he faced a number of setbacks.
From Los Angeles Times ● Apr. 5, 2026
Last year, some 1,000 U.S. troops withdrew from neighboring Niger, ending a nearly decadelong partnership that was the keystone of U.S. counterterrorism operations in the region.
From The Wall Street Journal ● Nov. 2, 2025
Standing under the narrow arch I glanced up, wondering if that keystone too was mortared with bone and blood.
From "The Left Hand of Darkness" by Ursula K. Le Guin
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