They are very similar. u003ca href=u0022https://en.wikipedia.org/wiki/Tortilla_soupu0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003eTortilla soupu003c/au003e is a traditional Mexican soup, whereas u003ca href=u0022https://en.wikipedia.org/wiki/Taco_soupu0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003etaco soupu003c/au003e is more of a Tex-Mex version. They have similar ingredients, so to be honest I think it's valid to use the terms interchangeably - I'd even be happy to call this one 'fajita soup' too!