A couple of weeks ago, a colleague used the word “Mastery” in a meeting, then stopped, looked at me with a lopsided grin and said: “force of habit. Sorry – I know you hate that word”. Another colleague chuckled and everyone shared ‘aww, what is she like?’ looks. The next time the opportunity to use it arrived, she hastily amended it from what she was originally going to say: “and that leads to mastery in the classroom” to the ever-so-slightly more vague “and that leads to, uh, great stuff happening”. But she’d changed it. And she’d changed it for me.
She shouldn’t have. Oh sure, she should have changed it, but not because someone else didn’t like it – she should have changed it for other, much more valid reasons. But before I go any further, I want to check the etymology of this word and see where it leads me.
.. mastery (n.)

early 13c., mesterie, “condition of being a master,” also “superiority, victory;” from Old French maistrie, from maistre “master” (see master (n)).

Ok, so… Master: .late Old English mægester “one having control or authority,” from Latin magister (n.) “chief, head, director, teacher” (source of Old French maistre, French maître, Spanish and Italian maestro, Portuguese mestre, Dutch meester, German Meister), contrastive adjective (“he who is greater”) from magis (adv.) “more,” from PIE *mag-yos-, comparative of root *meg- “great” (see mickle). Form influenced in Middle English by Old French cognate maistre. In academic senses (from Medieval Latin magister) it is attested from late 14c., originally a degree conveying authority to teach in the universities. 
What does it mean, then, to master? master (v.) 

early 13c., “to get the better of,” from master (n.) and also from Old French maistrier, from Medieval Latin magistrare. Meaning “to reduce to subjugation” is early 15c.; that of “to acquire complete knowledge” is from 1740s. Related: Mastered; mastering.
Three things leap out at me from these words:

1) the connotations of mastery are entirely male.

2) Mastery has to do with subjugation.

3) Mastery is concerned with “complete knowledge”.
It is no accident that so much of our academic language – particularly the soundbite language – has so many male connotations. There may be more female teachers than male, but the gender balance of teachers is largely irrelevant. The gender balance of social engineers and policy makers, however, may be a whole lot more relevant! I do not believe, by the way, that they are sitting in darkened chambers, glass of port in one hand, ornately-carved pipe in the other, evilly plotting the dominance of masculine language in education. I simply believe that no-one much thinks about the language they are using. In true soundbite fashion, as long as it sounds good, baby: it’s in.
This lack of accuracy over language use starts to cause problems quite quickly. I spoke to a teacher a few weeks ago who used the word ‘mastery’ and the phrase ‘growth mindset’ in the same sentence. Well now, hang on a minute: you can’t have Mastery if you believe in a growth mindset. As a quick peek at the etymology shows, Mastery is inextricably bound up with “complete knowledge”. If you promote the “growth mindset” approach, then you’re going to have to leave that word, Mastery, behind, I’m afraid. 
I don’t understand why we are so reluctant to be as precise as we can with the language we use. Imagine the maths teacher: “James, what is the sum of 3 and 8?

James: “Umm, 10, Miss”

Sally: “No it isn’t, it’s 12!”

Miss: “yeah…either is fine”.
Why are we so careless with our language when we know how powerful it can be? Why are we so happy to use a word that sounds good, without even considering what it means, what its connotations might be? 
I do not want my daughter growing up with language that, however subconsciously, defines and reinforces a gender stereotype that is not conducive to her dreams, her goals and her view of herself as a strong, independent individual PERSON. I don’t want my children, or my students -male or female – to grow up with language being used so carelessly around them. I do not want my teenage students growing up, having had the belief ingrained into them that anything that is great, anything that leads the way, anything that subjugates and oppresses, is male. It perpetuates divisions; it perpetuates dominance; it perpetuates subjugation. And that cannot be A Good Thing.
I also do not want my students, or my children, growing up with the belief that language really isn’t all that valuable, or important. Words, meanings, are interchangeable, valuable only if they sound good. Teach children to devalue language at your peril: our society, our culture, with all its richness and diversity, will be all the poorer for it.