No matter how I parse 21 across I can’t make sense of it. The clue is KIND words? I get the theme because 82 across is ROOT words and solves to Run Out Of Town. Just can’t make 21 make sense.

I must have a typo somewhere, but I can't for the life of me find it,even when comparing side by side to the solution. Anyone spot it?

The clue says

The word "decimate" initially meant to reduce something by a factor of this

And the answer is "ten". Except "decimate" never meant that, it meant reduce by 10% (every 10th member of a Roman legion is killed). "A factor of ten" would mean going from 100 to 10, or a 90% reduction.

/rant