Of course this expression referred to super popular 90's teens sitcom with the same name.

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Of course that's a bold faced lie, and in fact it doesn't even have anything to do with a school bell either.

This expression means that you were saved just in the nick or time, or saved at the very last minute.

You could use it in the following way;

When telling your friend how you got out of big project at work because your shift was over, you could say 'I was saved by the bell"

The expression actually originates from these safety coffins from the good old days, when it was common to bury people alive. I mean really it's hard to tell if someone is dead or just sleeping right? Someone had to work the 'graveyard shift' to listen for the 'dead ringers' to be "saved by the bell".

You could also get the safety coffin with the flag in case the guy that was going to save your life was def.

Sorry those were all lies

Well not lies, but erroneous theories about how all three of those expressions (dead ringer, graveyard shift, saved by the bell) started. It's certainly much more fun and interesting then the real ones. It's always interesting to hear how these alternate origin stories got started and then popularized due to the internet. (fake news anyone).

So on with the real origin

Like I said it's not as much fun as above, it actually related to boxing, when the bell at the end of the round stopped the fighting so the combatant had a chance to rest. Or even the final bell which meant you no longer had to fight at all.

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Now your smarted and can impress your friends, also you won't go around spreading lies anymore

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