Õ: mitte tasand ( = plane)

olemus
hierarhiatase hargliigituses
= a level in a classification hierarchy

näiteid
https://www.allenisd.org/cms/lib/TX01001197/Centricity/domain/1578/unit%207/Classification%20Notes%20for%20Website.pdf

https://duckduckgo.com/?q=classification+level&t=h_&iax=images&ia=images