Are all the different meanings of "bolt" related? A workmate recently used it to mean a crossbow's projectile; Zeus chucked thunderbolts, drapers use bolts of cloth, I use bolts to fasten things together, and there's a bolt that blocks the breech in my rifle. Any other meanings I've missed?

All the meanings you mention are related. There's also the verb with meanings including "to start, spring; to dart forth; to run to see prematurely; to break away from a political party." This was derived from the noun.

There's also bolt, boult "to sift; to pass through a sieve or bolting-cloth" and bolt, boult "a flour-sieve" which have a different etymology.

The OED adds these definitions:

Wood in special size for cleaving into laths.

Bookbinding. The fold at the top and front edge of a folded sheet.

And of course, you bolt food down when you're really hungry.

Then there's the bolt you make for the door after bolting your food.

quote:

Originally posted by arnie:
Then there's the bolt you make for the door after bolting your food.

Which might be problematic if the door is bolted.