behalf

noun

be·​half bi-ˈhaf 

-ˈhäf,

bē-

: interest, benefit

also : support, defense

argued in his behalf

On Behalf of vs. in Behalf of: Usage Guide

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.

Phrases

on behalf of or in behalf of

: in the interest of

also : as a representative of

I wrote the letter on behalf of my client.

Examples of behalf in a Sentence

Recent Examples on the Web

No math is necessary on the traveler's behalf since flight times are already calculated by the airline. —Kathleen Wong, USA Today, 2 Nov. 2025

According to Hamilton Lane, a firm that invests on behalf of pension funds, as of 2021 PE firms were still holding 45% of their buyout deals five years following their purchase; last year, around 65% were still sitting unsold after a half-decade. —Shawn Tully, Fortune, 1 Nov. 2025

She was not authorized to speak on behalf of NASA. —Josh Dinner, Space.com, 31 Oct. 2025

Agentic commerce typically occurs when a consumer sends an AI model out to shop on their behalf. —Meghan Hall, Sourcing Journal, 31 Oct. 2025

Word History

Etymology

Middle English, from by + half half, side

First Known Use

14th century, in the meaning defined above

Phrases Containing behalf

• in behalf of someone
• in someone's behalf
• on behalf of someone
• on someone's behalf

Rhymes for behalf

• carafe
• digraph
• distaff
• falstaff
• giraffe
• subgraph
• autograph
• biograph
• cenotaph
• chronograph
• epigraph
• epitaph

Kids Definition

behalf

noun

be·​half bi-ˈhaf 

-ˈhȧf

: useful aid : support

spoke in my behalf