1400–50;late Middle English;Middle Englishbihalve, earlier as adv. and preposition with the sense “near(by),” orig. as prepositional phrase bi halve on one side; see be-, by1half
interest, part, benefit, or respect (only in the phrases on (someone's) behalf, onor US and Canadianin behalf of, in this (orthat) behalf)
Old English be halfe from be by + halfe side; compare Old Norse af halfu
On behalf of is sometimes wrongly used where on the part of is intended. The distinction is that on behalf of someone means `for someone's benefit' or `representing someone', while on the part of someone can be roughly paraphrased as `by someone'. So, the following example is incorrect: another act of apparent negligence, this time not on behalf of the company itself, but on behalf of its banker, when what was meant was there was negligence by the company's banker