vest, singlet, banian

What are the differences between these dresses: vest, singlet, banian?

I don’t know, but, just so’s you know, the word “banian”, which seems to be more often spelled “banyan”, is hardly used in the UK, and I think many people would not know what it meant. I think it would only ever be used in an “ethnic” way, to refer to garments worn by Indians or Pakistanis, not as a generic word like “vest”.