Constantness vs. Constancy: What's the Difference?

The state or quality of being constant.

Steadfastness, as in purpose or affection; faithfulness.

The condition or quality of being constant; changelessness.

(uncountable) The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc.

(countable) An unchanging quality or characteristic of a person or thing.

The state or quality of being constant or steadfast; freedom from change; stability; fixedness; immutability; as, the constancy of God in his nature and attributes.

Fixedness or firmness of mind; persevering resolution; especially, firmness of mind under sufferings, steadiness in attachments, or perseverance in enterprise; stability; fidelity.

The quality of being free from change or variation

The tendency for perceived objects to give rise to very similar perceptual experiences in spite of wide variations in the conditions of observation

Faithfulness in personal attachment (especially sexual fidelity)