Proscription vs. prescription

To proscribe is to rule out. To prescribe is to rule in. Proscriptive grammar says what's wrong and what isn't allowed. Prescriptive grammar is the type of grammar I'm hoping to write here -- advice on what TO do, rather than what not to do.

On the surface, these are unusual uses of the Latin roots "pro" and "pre," along with the more obvious "scribe" for "write." We're used to "pro" being "for" something, and "pre" meaning "before," although I'm pretty sure that's Greek, not Latin. The Latin root "pro" can mean "out" in various other contexts: to profess is to say something outwardly, whereas to confess is to reveal something more intimately. To progress is to move outward or forward, whereas to regress is to move backward. "Prescribe" is derived from the Latin word "praescribere," meaning to write at the beginning, dictate, or order, according to Merriam-Webster's online dictionary. Its cousins are probably more distant, as I'm having trouble identifying other words that use "pre" with the same sense of dictating or telling someone what to do. If you think of any, let me know.