word usage - Is it correct to use "branch" to describe type of industry?

I've always used the word branch when describing the type of industry, line of business or operation category. Please note that I'm not referring to a part of a concern structure as in "Scranton branch of Dunder Mifflin".

For instance, to express that John is in finance and doesn't understand the importance of well defined code structure, which a programmer or other IT professional definitely would, I'd state the following.

"Jonh doesn't know jack. He's not in our branch."

I've never got eye browse arousal on this so I lived happily ignorant that it might be an incorrect usage of the Swedish term (borrowed word from English) until my colleague had the cruelty to point that out for me.

I tried to defend my position with an online dictionary but apparently there's a bug in their logic because it only confirmed the said colleague's critique of my expression. :)

Seriously speaking, though, I'd like to get some light shed on the usage of the term. Is it understandable? Commonly used? Poetically or metaphorically expressed? Just plain wrong?

Answer

The best word for this idea depends on the context.

Within a company: As you allude to in your question, branch is appropriate for referring to other offices within the same company. To distinguish colleagues by role rather than location, you can use department or division. Many companies will have additional local jargon along those lines, like job function, organization, role, or silo.

Generally: For people who don't (necessarily) work for the same company, you can talk about different fields, industries, sectors, or specialties, depending on the nature of the difference. For example, industry and sector generally refer to very broad categories like finance, government, manufacturing, military, and non-profit, whereas field and specialty usually refer to different roles within the academic, engineering, and scientific sectors.