defining

American  

[dih-fahy-ning] / dɪˈfaɪ nɪŋ /

adjective

1. decisive; critically important.

   Taking a course in architecture was a defining turn in her life.

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Other Word Forms

• nondefining adjective
• self-defining adjective

Explanation

Something defining is essential to what something is. A defining moment in your life helps makes you what you are. In the dictionary, definitions tell you what words mean, and the similar word defining has to do with what things are too. The defining characteristic of a chair is that you sit on it. The defining feature of food is you can eat it. People have defining features too: if you went to a summer camp and had an amazing time, it could be a defining time in your life. Defining things helps shape and mold us.

Example Sentences

He is expected to delivered prepared remarks about the two nations’ shared history and their enduring diplomatic ties, while offering measured acknowledgment to the tensions defining the current moment.

From Los Angeles Times • Apr. 28, 2026

Researchers have uncovered several defining characteristics that help explain why SuperAgers maintain such strong cognitive abilities:

From Science Daily • Apr. 23, 2026

It’s also the defining public-health issue of our time.

From MarketWatch • Apr. 23, 2026

A big question will be whether Ternus has "the appetite for the kind of bold, occasionally uncomfortable decisions" that defining an Apple AI platform will require.

From Barron's • Apr. 21, 2026

She smiled, teasing, “There’s gotta be something here for you, Mariah. Besides, you can’t have only one defining personality trait.”

From "Legendary Frybread Drive-In" by Cynthia Leitich Smith