Simplest answer: In some countries, notes were called by alphabet letters - in other countries they were called by the Do Re Mi names. So if you asked your question of anybody in those countries, they'd just say (in their respective languages), "note names". That's all they were - the names of the notes.
Meanwhile it's gotten more complicated, because in some countries that use ABC there are also philosophies of there being something special about the Solfege names. For example "Sol" also meaning "sun". Or that they are easier to pronounce we should use those names instead of ABC, for example in sight singing. So now we do need a name. "Letter names notes" (I think) vs. "Fixed Do Solfege".
"fixed Do" vs. "movable Do" Solfege - because "movable Do" also exists. This is where Do represents the Tonic note in a key. Thus in G major, G is Do: in Eb major, Eb is Do. As in the "Do a Deer" song.
Meanwhile, countries that actually name the notes (pitches) via Do Re Mi - may also be working with "movable Do". Canada is officially bilingual French/English. French uses Do Re Mi - English uses ABC. The RCM theory books have included movable Do solfege in their more recent editions. Thus I imagine that French Canadians are dealing with both movable Do and fixed Do names.
Topic: ABC vs. Do Re Mi