Commensurate, a.
1. Having a common measure; commensurable; reducible to a common measure; as, commensurate quantities.
2. Equal in measure or extent; proportionate. Those who are persuaded that they shall continue forever, can not choose but aspire after a hapiness commensurate to their duration. Tillotson.
1 other Webster entry under this spelling
Commensurate, v. t. [imp. & p. p. Commensurated; p. pr. & vb. n. Commensurating.]
1. To reduce to a common measure. Sir T. Browne.
2. To proportionate; to adjust. T. Puller
Shades of meaning
Fernald has no entry of its own for commensurate; he lists it under adequate.
Where he writes about it:
Adequate, commensurate, and sufficient signify equal to some given occasion or work; as, a sum sufficient to meet expenses; an adequate remedy for the disease. — from adequate
Commensurate is the more precise and learned word, signifying that which exactly measures the matter in question. — from adequate