In that case, I might have to look for my sisters old school dictionary. It should be sufficient. Hopefully.
I completely forgot about the janitors closet. Yes, that would be a great place to go for make-shift weapons.
metal brooms or mops
Even a wooden broom handle would be useful, if you couldn't find anything else that is better. I don't think the mop* would be as good as the broom. Brooms are easy to dismantle, all you have to do it unscrew or cut/break off the end.
*or atleast the ones with a sponge on the end and have those mechanisms that help you squeeze out the excess water.
but if they're already knocking go for the arm curl station and grab a smaller bar.
What's an arm curl station? Or is that something I should google/wikipedia rather than ask people?
flammable chemicals/bleach + ammonia*
It would be unwise to test out something like if chemical weapons are useful against zombies while you're running for your life. If it doesn't even effect the zombie and it gets you, then it would have been the biggest mistake in your life. Although, it might be a good idea to try out once you are relatively safe, like if you were on top of a building from which you could drop the chemicals onto unsuspecting zombies.
If you were at high-school/university/collage then the metal/wood technology room could be a great place to go. There would be a large amount of tools (like hammers) that you could use and probably a large amount of wooden polls/metal bars/pipes. They would be great weapons untill you fond something better; like a crowbar. (I am only talking about melee fighting here, ranged would be preferable but we do have to plan for every contingency, like when you run out of ammo or never ever find a gun or it is Z-day and you were caught unprepared).