while reading my british harry potter books we've discovered that the words study and revise are used almost interchangeably. we (myself, my husband, and my parents-in-law) have never seen this use of the word revise. it seems that revise may have more to do with preparing for a final exam and studying is the more all-purpous word, though at one point both are used in the same sentence. my dictionary does not elucidate. (the american version of the book uses study exclusively)

what, if any difference is there between the two words?

take a look at how the word has evolved:

†1. intr. To look again or repeatedly at, to look back or meditate on, something. Obs.
†2. trans. To see or behold, to look at, again.
3. a. To look or read carefully over, with a view to improving or correcting.
b. To go over again, to re-examine, in order to improve or amend; †to condense by revision.
c. To go over (a subject already learnt) in preparation for an examination. Also absol.


so the study usage is in the sense of 'review'.

Re-vision. Re-view. =To see or behold, to look at, again
I LOVE language!

In my understanding of colloquial English in England, revision automatically implies preparation for a test or exam; study might be anything from review of existing work through to primary research. In the sort of school conditions Rowling describes, you might get study periods every evening and (for higher level subjects) independent study periods also during the daytime timetable, but revision would only get timetabled in the immediate proximity of exams.

No, no, no: revison ONLY means: 3. a. To look or read carefully over, with a view to improving or correcting.

To prepare for a test, you STUDY. You study your notes and try to memorize facts--if you REVISE your notes, you might change them enough to cause you to fail the test.
CK, I see no reason to change my usage of a perfectly good and understood word, just because some old-timey Limeys took it upon themselves to change the meaning...

CK, I see no reason to change my usage of a perfectly good and understood word, just because some old-timey Limeys took it upon themselves to change the meaning...

Ah, so you're not prepared to take a revisionist standpoint on the use of the word, then?

Ha! Nope, CK, I studied my options, and I'm standin' my ground.

I was out in my shop (where I've been working too hard to have time for the finer things in life like AWAD) when a large piece of wood fell out of the clamp onto the floor. I picked up the wood and revised it. I tried telling it over and over again to stay up by itself and it wouldn't. Insist is nice but vise is best.

TdE

I tried
telling it over and over again to stay up by itself and it wouldn't.

Have you tried Viagra?

Add-vise and it will consent.

and Geoff, another woodpecker joke?

and Geoff, another woodpecker joke?
Ohmigawd--you get a point for that one, that's for sure! TdE, you might wanna rethink that "vise is best"...

Insist is nice but vise is best.

Do you US'ns pronounce vise as vice or vize? In UK it is spelt and pronounced vice, hence the sadist's mantra "Vice is nice, but a G-clamp is much more effective if you can find the right spot"

Do you US'ns pronounce vise as vice or vize?

US'ns pernounssez it with a voiced labiodental fricative and a unvoiced sibilant. The plural keeps the unvoiced sibilant but adds a voiced one for the plural marker. Vicez.

revision automatically implies preparation for a test or exam

So a(n) historical revisionist is someone studying for a final exam in a history class rather than someone who has reviewed historical documents and decided that the received wisdom on the past events is misguided?

nope. Revision is only related tangentially to revisionist in the colloquial pattern I know; you would never, for the converse example, say that someone studying for an exam was a revisionist.