constancy

American  

[kon-stuhn-see] / ˈkɒn stən si /

noun

1. the quality of being unchanging or unwavering, as in purpose, love, or loyalty; firmness of mind; faithfulness.

   Synonyms:

   devotion, loyalty, fealty, fidelity, resolution

   Antonyms:

   infidelity, irresolution

2. uniformity or regularity, as in qualities or conditions; invariableness.

   Synonyms:

   dependability, permanence

   Antonyms:

   variability

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constancy British  

/ ˈkɒnstənsɪ /

noun

1. the quality of having a resolute mind, purpose, or affection; steadfastness

2. freedom from change or variation; stability

3. psychol the perceptual phenomenon in which attributes of an object appear to remain the same in a variety of different presentations, e.g., a given object looks roughly the same size regardless of its distance from the observer

4. ecology the frequency of occurrence of a particular species in sample plots from a plant community

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Etymology

Origin of constancy

From the Latin word constantia, dating back to 1520–30; see constant, -ancy

Explanation

Something or someone that never changes, that stays the course, and that is more like a rock than a leaf blowing in the wind shows constancy. Have you ever noticed how some people change their minds every day? Someone like that isn't showing constancy. In parts of the world where the weather changes frequently, the weather has no constancy, whereas in San Francisco, where it's about 70 and mild for ten months of the year, the weather has constancy. If you take constancy — a good thing — too far, you have stubbornness — an undesirable quality.

Example Sentences

But its biggest power lies in its constancy.

From BBC • Jun. 23, 2025

“Younger children in particular, they rely on constancy in their lives to feel like everything’s OK,” said clinical psychologist Karen Rogers, of the National Center for School Crisis and Bereavement at Children’s Hospital L.A.

From Los Angeles Times • Jan. 18, 2025

Building a community culture that offers a sense of constancy and support can have a powerful impact on a child’s education journey, says Ryan Quigtar, Renton Innovation Zone Partnership’s executive director.

From Seattle Times • Nov. 24, 2023

With the ubiquity of Zoom meetings, FaceTime calls, selfies and the constancy of documenting our lives on social media, access to our own image can often feel inescapable.

From Scientific American • Oct. 9, 2023

These early equation-laws were extremely good at expressing simple relationships, but equations have limitations—their constancy, which prevented them from being universal laws.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Related Words

• dependability
• perseverance
• steadfastness
• steadiness
• trustworthiness
• truthfulness