Student or Learner
The two rows of lanterns that led to the dais were wide enough apart that the four of them were able to walk side by side.
(C. Paolini; Inheritance)
Have I understood it right that I can say something like the following:
"It was deep enough under the water that nobody could reach it."
"This plane flies high enough above the ground that nobody can see it." etc.
Yes, I believe you have understood the usage.