commensurable

Commensurable means "having a common measure" or "corresponding in size, extent, amount, or degree." Its antonym incommensurable generally refers to things that are unlike and incompatible, sharing no common ground ("incommensurable theories"), or to things that are very disproportionate, often to the point of defying comparison ("incommensurable crimes"). Both words entered English in the 1500s and were originally used (as they still can be) for numbers that have or don't have a common divisor. They came to English by way of Middle French and Late Latin, ultimately deriving from the Latin noun mensura, meaning "measure." Mensura is also an ancestor of commensurate (meaning "coextensive" or "proportionate") and incommensurate ("disproportionate" or "insufficient"), which overlap in meaning with commensurable and incommensurable but are not exact synonyms.