“equal”

Corresponding in size, degree, or extent; proportionally equivalent.

“Her salary was finally commensurate with her decade of expertise.”

Best for: Ideal in professional or academic writing when discussing proportional fairness.

Equivalent in effect, value, or meaning to something else.

“Refusing to testify was tantamount to an admission of guilt.”

Best for: Best used when drawing a strong, often dramatic equivalence between two things.

Having the same rank, status, or authority as another.

“The two branches of government were designed to be coequal in power.”

Best for: Works well in legal, political, or institutional contexts emphasizing parity.

Having equal force, power, or validity.

“The two arguments were equipollent, leaving the jury utterly undecided.”

Best for: Rare philosophical and logical term; striking in formal essays or debate contexts.

Of or relating to equality of law or political rights among all citizens.

“The reformers demanded an isonomic society where birth granted no legal privilege.”

Best for: Highly specific to political philosophy and historical discourse; impressive in scholarly writing.

Having the same boundaries, scope, or duration as something else.

“His ambition was coterminous with the empire itself — limitless and consuming.”

Best for: Elegant literary choice when describing two things that perfectly overlap in scope or time.