Crossword Genius

Domination by a schoolteacher? (7)

Ross

I believe the answer is:

mastery

I'm a little stuck... Click here to teach me more about this clue!

This could be a double definition.

'domination' is the first definition.
(I know that mastery is a type of domination)

'a schoolteacher?' is the second definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'by' acts as a link.

Can you help me to learn more?

(Other definitions for mastery that I've seen before include "Expert skill" , "Grasp" , "Supremacy" , "Total control" , "in full command" .)

Want a hint initially instead of a full solution? Install my app