Bedeutung von “mastery” — Learner’s Dictionary

mastery

noun [ U ] us uk /ˈmɑːstəri/
mastery of sth

great skill or understanding of something:

his mastery of the Japanese language
mastery of/over sth

control over something:

The two countries battled for mastery over the region.

(Definition von “mastery” aus dem Cambridge Learner's Dictionary © Cambridge University Press)