Commute, v. t. [imp. & p. p. Commuted; p. pr. & vb. n. Commuting.]
Etymology: [L. commutare, -mutatum; com- + mutare to change. See Mutation.]
To exchange; to put or substitute something else in place of, as a smaller penalty, obligation, or payment, for a greater, or a single thing for an aggregate; hence; to lessen; to diminish; as, to commute a sentence of death to one of imprisonment for life; to commute tithes; to commute charges for fares. The sounds water and fire, being once annexed to those two elements, it was certainly more natural to call beings participating of the first "watery", and the last "fiery", than to commute the terms, and call them by the reverse. J. Harris The utmost that could be obtained was that her sentence should be commuted from burning to beheading. Macaulay.
1 other Webster entry under this spelling
Commute, v. i.
1. To obtain or bargain for exemption or substitution; to effect a commutation. He . . . thinks it unlawful to commute, and that he is bound to pay his vow in kind. Jer. Taylor.
2. To pay, or arrange to pay, in gross instead of part by part; as, to commute for a year's travel over a route.
Shades of meaning
Fernald has no entry of its own for commute; he lists it under change.
Where he writes about it:
To commute is to put something easier, lighter, milder, or in some way more favorable in place of that which is commuted; as, to commute capital punishment to imprisonment for life; to commute daily fares on a railway to a monthly payment. — from change