Recently, I was scanning around the web looking to see if I could find coats of arms belonging to my family.
I also found a site here that explains meanings and concepts behind them. Pretty cool.
Technically, you're not supposed to use them unless you can prove descent.
Bugger that!
Anyway...

This is the crest for the family of my paternal grandfather.
Apparently
Stag = One who will not fight unless provoked; peace and harmony
Arrow = Readiness (for battle); if depicted with a cross, represents an affliction

This is the "badge" (since they be Scottish) from the family of paternal grandmother.
The meanings aren't as easy.
But apparently
Crown = Royal authority
Woohoo!

O'Brien is the surname of my maternal grandfather's family.
Lion (Here the lion is "passant guardant") = Dauntless courage

This one is a bit dodgy, as my maternal grandmother's surname was actually Bazzo, not "Basso". Still, it was the closest I could find. (Ignoring that they were dirt poor farmers and probably never had any coat of arms....)
Helmet = When depicted on the shield, denotes wisdom and security in defense; strength, protection, invulnerability
Cross = Faith; Christianity; Service in the Crusades
....or it could all be a big load of steaming crap.