Usage Discussion of behalf
A body of opinion favors in with the “interest, benefit” sense of behalf and on with the “support, defense” sense. This distinction has been observed by some writers but overall has never had a sound basis in actual usage. In current British use, on behalf (of) has replaced in behalf (of); both are still used in American English, but the distinction is frequently not observed.
Origin of behalf
Middle English, from by + half half, side
First Known Use: 14th century
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