The designation "Objectivist" was made in 1931 when Louis Zukofsky edited the February issue of Poetry: A Magazine of Verse at the urging of Ezra Pound. The magazine contained the work of Zukofsky himself, Charles Reznikoff, Carl Rakosi, George Oppen, Basil Bunting, William Carlos Williams, Kenneth Rexroth, and many lesser-known poets. The name came about because of Harriet Monroe's (the then-editor of Poetry) request for a group title. As is often the case, the group name was more a matter of convenience to describe the poets' connections to one another than it was a consciously set forward program.
Zukofsky describes the founding of Objectivism in Prepositions: The Collected Critical Essays of Louis Zukofsky:
When I was a kid I started the Objectivist movement in
poetry. There were a few poets who felt sympathetic
towards each other and Harriet Monroe at the time
insisted, we'd better have a title for it, call it
something. I said, I don't want to. She insisted; so, I
said, alright, if I can define it in an essay, and I used
two words, sincerity and objectification, and I was
sorry immediately. But it's gone down into the history
books; they forgot the founder, thank heavens, and
kept the terms, and, of course, I said objectivist, and
they said objectivism and that makes all the difference.
Well, that was pretty bad, so then I spent the next
thirty years trying to make it simple.