Meaning : The quality of being enduring and free from change or variation.
Example :
Early mariners relied on the constancy of the trade winds.
Synonyms : stability
Meaning : (psychology) the tendency for perceived objects to give rise to very similar perceptual experiences in spite of wide variations in the conditions of observation.
Synonyms : perceptual constancy
Meaning : Faithfulness and dependability in personal attachments (especially sexual fidelity).