It seems backwards, but when my kids take an hour off from their schoolwork they call it a "study break" --- not a "play video games break" or a "fix a snack break" or a "surf the web break". It sounds a lot better to label the time by what one is not doing, eh?!
KID #1: See, the reason it's called a STUDY break is that it's a BREAK from STUDYing. If it were a videogame break, it would be a BREAK from VIDEOGAMEs. People took lots of videogame breaks at the LAN party, and we got some pizza or chips to munch.
... but then at the office why is it called a "coffee break" or a "lunch break" or a "smoke break" --- why not name them all "work breaks"? - ^z
KID #2: Specificity. "Work breaks" vary widely in type, as you pointed out, but "study breaks" are (nearly) always the same kind - a period of videogaming.
Actually, scratch that. When students take a break, it is because they want to stop studying; when employees take a break, it is because they want to drink coffee, eat lunch, or smoke tobacco. Therefore, the name reflects the thought of the slackoff, erm, speaker.
Mmm, purpose or locality may be equally relevant depending on perspective. Human semantic usage is so full of possibilities.