I am trying to understand a question from a test that uses the term "256-dimensional Euclidean orthonormal hyperspace". I don't know what that term means (my math knowledge is only high school level). The test says one may need "to make small queries about the meaning of some words", but Google did not help. So I ask if the meaning of this term can be explained for someone with just knowledge of high school math (maybe there is some YouTube video explaining?).
Thank you!