American here. Noodles are anything that generally fits the archetypal foodstuff paramaters of Spaghetti regardless of shape or preparation. (eg hard flour and egg product you boil as a base for a meal.)

Tagliatelle included. Spaghetti is also a noodle, but it refers specifically to spaghetti form factor. Basically Americans only know the name of a handful of pasta shapes so it all gets rolled up into noodles. Pasta is also used interchangeably with Noodles.

You'll get blank stares if you refer to a pasta by its correct name as only Spaghetti, penne, bowtie, lasagna, and macaroni pasta are generally recognized. They'll probably identify it is a noodle, but they just wont know what it is without looking it up.

Knowing obscure pasta names is a sign of sophistication in the US.