Origin: Germanic Old English prefix
Behalf has 3 different meanings across 1 category:
as the agent of or on someone's part (usually expressed as `on behalf of' rather than `in behalf of')
"the guardian signed the contract on behalf of the minor child"
"this letter is written on behalf of my client"
for someone's benefit (usually expressed as `in behalf' rather than `on behalf' and usually with a possessive)
"in your behalf"
"campaigning in his own behalf"
"spoke a good word in his friend's behalf"
The interest, benefit, or wellbeing of someone or something.
"The community rallied together for the common good."
In plain English: Being on behalf of someone means acting for them or doing something to help their interests.
"She spoke on behalf of the entire committee during the meeting."
Usage: Use "on behalf of" to indicate that you are acting for the benefit or interest of another person or group. This phrase signals that your actions represent their needs rather than your own personal gain.
The word "behalf" comes from the phrase bī healfe in Old English, which literally meant "by his or her side." It entered Middle English as bihalve, meaning "nearby," before evolving into its modern sense of acting on someone's interest.