A group of advisers or experts. It’s usually used to refer to a group of people supplying advice to another person – so they are a brain trust to someone else.
Specifically, three professors at Columbia were known as “the Brain Trust” to FDR during his 1932 presidential campaign.
Why I Looked It Up
I was watching a video where someone said:
The team I was working with became a bit of a brain trust…
Also, when I was a kid, there were a group of older kids that would hang on out on the corner of our street. They were a little rough around the edges, and whenever we drove past them, my dad would say, “There’s the neighborhood brain trust.” I ever quite knew what he meant, just that it was an sarcastic insult of some kind.
So, I weirdly have a negative impression of the word. Whenever anyone says “brain trust” I think they’re poking fun at the subject. I was sort of expecting that connotation to be confirmed, but it turns out that this is just me, I guess.
Added on August 8, 2022
From the book Narrative Economics:
Raymond Moley, one of President Franklin Roosevelt’s “Brain Trust” experts during the Great Depression…
Moley was a law professor at Columbia.
Added on August 21, 2022
I encountered the word again in Too Big to Fail:
What Barclays needed was a partner – a big, rich one – and it was a matter that Diamond knew he had to discuss with his brain trust…
Added on September 11, 2022
In Creativity, Inc. there is a lot of discussion about the “Brain Trust” at Pixar, which was a group of senior executives that would come together to discuss a project and make sure it was still on track. This was eventually renamed the “Story Trust.”