commuted to

Yokohama in 1872 by Paul Blumを読んでいます。当時横浜には各国のconsular courtsがあったそうです。
It was only the British who maintained, until the turn of the century, a court of law in Yokohama complete with judicial machinery and trained judges.
...
A Mrs. Carew was accused of the arsenic poisoning of her husband.
Mrs. Carewはthe British consular courtで絞首刑を言い渡されます。　しかし、その後、
Mrs. Carew was not hanged. Her sentence was commuted to life imprisonment by Sir Ernest Satow, then Minister to Tokyo, and, some years later, while serving her time in England, she obtained a full pardon.
上の文に出てくる "commuted to" は文脈からして、絞首刑から終身刑に減刑されたの意味だと容易に推測できますが、 "commute" の意味として、通う、通勤するなどの意味しか知らなかったので意外です。辞書で意味を確認します。
・Merriam-Webster's Online Dictionary: to change (a penalty) to another less severe: commute a death sentence to life in prison
・Cambridge English Dictionary: to change a punishment to one that is less severe: Her sentence was commuted from death to life imprisonment.
語源を調べると元々 "commute" には "change" の意味があり、通う意味の方は後からでした。
・Online Etymology: mid-15c., from L. commutare "to often change, to change altogether," from com-, intensive prefix (see com-), + mutare "to change" (see mutable). Sense of "make less severe" is 1630s. Sense of "go back and forth to work" is 1889, from commutation ticket "season pass" (on a railroad, streetcar line, etc.), from commute in its sense of "to change one kind of payment into another" (1795), especially "to combine a number of payments into a single one."