In American English, we usually refer to the thin ones as “french fries” or simply “fries”. Usually “french” rather than “French”, since the fries are actually made in America; “french” is just the name of the dish). Thicker ones may be called “home fries”. There’s also a less common version called “curly fries” served at some restaurants. All the above would probably be 土豆条.
The French, who actually associate them with Belgium, just call them “fries” or “fried potatoes”. “Potato” is “pomme de terre” (earth — i.e. the ground — apple) in French, usually abbreviated to “pomme” (apple).
I found 土豆丝 in an image search, and it appears to be some sort of grated potato dish. The pictures don’t look exactly like anything I’ve ever had, but they may be similar to what we call hash-browns.