The state or quality of being equivalent; having equal value, meaning, or effect.
From Latin 'aequivalens' (equal in value), combining 'aequus' (equal) and 'valens' (strong, worthy). The suffix '-cy' forms an abstract noun denoting a state or condition, evolving from medieval Latin legal terminology.
Equivalency became crucial in modern chemistry and physics—when scientists realized that mass and energy are equivalent (E=mc²), it fundamentally changed how we understand the universe. The word bridges mathematics, law, and science in surprisingly deep ways.
Complete word intelligence in one call. Free tier — 50 lookups/day.