Equipollency is a term that refers to the state of being equal in significance or power. Some synonyms for this concept include parity, equivalence, similarity, correspondence, and commensurability. These words all convey the idea of two or more things having identical or comparable qualities or attributes. Other related terms include congruity, consistency, compatibility, and harmony. Whether used in the context of mathematics, philosophy, or everyday language, equipollency and its synonyms carry a sense of balance and harmony, suggesting a state of affairs where things are in agreement and nothing is out of place.