That would be strictly a coding term… which for users are just other objects. When we talk of developing a new “tool” though we have to discuss the technical coding aspects… and we need to able to use and pass “objectId” and “childObjectId” (vs the current toolId and objectId.)
Fushion 360… A “canvas” workspace is what you load an image into. It would be analogous to loading an image into the Seamly2D background. It’s named canvas because it’s sketch / paint related - not drafting related.
https://help.autodesk.com/view/fusion360/ENU/?guid=GUID-FBA87F37-2A42-47D2-B1C1-BED8423A7E55
I don’t think we’d confuse AutoCAD users by using the term “workspace”, but we might if we called it “canvas”. Not to mention as a pattern maker of 40+ years I’ve NEVER called what I’m making a pattern on - paper or screen - a canvas. BTW… while we’re on the subject… Canvas in Fusion is really a “tool”.