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

Derived Forms

• self-defining
  adjective
• nondefining
  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

“Neuromancer,” one of the defining cyberpunk novels, was published in 1988; that book imagines an interconnected, virtual reality world you can traverse by “jacking in.”

From Salon • Jun. 8, 2026

The tensions between the U.S. and Israel are becoming a defining characteristic of the current phase of the war, much as unprecedented close cooperation between the two allies marked its beginning.

From The Wall Street Journal • Jun. 8, 2026

By defining these perceptual attributes more rigorously, the researchers have supplied a missing piece in Schrödinger's long standing vision for a closed mathematical model of color.

From Science Daily • Jun. 7, 2026

The overall destruction, paired with the collapse of a major alliance, made 2025 a defining year for the game.

From BBC • Jun. 5, 2026

Race plays a major role—indeed, a defining role—in the current system, but not because of what is commonly understood as old-fashioned, hostile bigotry.

From "The New Jim Crow" by Michelle Alexander