-ance Also -ence, -ancy, and -ency.
A state or quality; a process or action.
[French -ance or -ence, from Latin -antia or -entia.]
Words in the a and e spellings have similar meanings. Which spelling is considered correct usually depends on the Latin word from which it derives. But the history of the suffixes is confused and inconsistent; many words have changed spelling in passing through French, and again in English. Modern creations use the spelling of their Latin precursors where one exists; with stems from other sources, the choice of ending is largely arbitrary.
Words in these endings may suggest a quality or state (confidence, ignorance, impertinence, protuberance), an amount or degree (conductance, pittance), or an action or process, or its result (emergence, furtherance, performance, reference, remittance, vengeance).
Latin -antia and -entia are also the source of English words in -ancy and -ency. These endings are more recent than -ance and -ence and suggest the idea of a quality or state, often an abstract one, without the idea of action or process. Examples are buoyancy, constancy, efficiency, infancy, piquancy, presidency, urgency and vacancy.
Because of the overlap in meaning between words in -ance and -ancy and those in -ence and -ency, a number of word pairs exist that have closely related senses, though one member is often rarer than the other: convergence and convergency, repugnance and repugnancy, irrelevance and irrelevancy, permanence and permanency.