I only used the word expat because you said immigrants are people who permanently move somewhere, so I assumed you were calling people something else if they were not planning to stay forever.

I'll rephrase it, please find a couple of examples where the seasonal agricultural workers from Mexico into the US are not called immigrants. Or could you tell me what you'd call someone who comes, becomes a resident and works for a 6months, 12 months contract? Or someone who moves to a different country to work for 5 years, fully intending to leave after?

The non immigrant visa is for people who visit your country but are not residents. They have restrictions on what they can do - very limited in terms of any work they can do and the visa is mostly used for tourists. I had one too, and yeah, I did not considered myself an immigrant into the US for the time I was visiting, but not because it was temporary, but because I was a tourist and had no plans to reside past my 2 weeks.

The word immigrant just means someone who lives somewhere outside of their country. It does not need to be for the rest of their lives, just to be a resident.