olemus
Wiktionary:
1. (intransitive) to practice an ability
She trained seven hours a day to prepare for the Olympics.
3. (intransitive) to improve one's fitness
I trained with weights all winter.

ISO/IEC 2382-36:
oskuste ja/või mõistmise arendamine
protseduuriliselt määratletud õpitegevustega,
mis keskenduvad konkreetsele rakendusele
= development of skills and/or understanding through procedurally defined learning activities focused on a specific application

vt ka
- õppus (2)