Welcome to OCDO.
The best you are going to get to a definition is what's out there in case law, as it and the act of open carrying are not defined in the Code of Virginia. That is why OC is the default carry option in Virginia - CC requires a CHP (special government permission slip) which gives you an affirmative defense for breaking the law against carrying as contained i 18.2-308.
Then you get into "hidden from common observation" - dear sweet shivering $diety are there more "definitions" out there about just what that is!
As for "any dirk, bowie knife, switchblade knife, ballistic knife, machete, razor, slingshot, spring stick, metal knucks, or blackjack; or  any weapon of like kind" - again, your answers are going to be found in case law. For even more fun, try to distinguish between a dirk and a dagger, a clip-point and a bowie knife, a switchblade and an automatic-sheath knife, a machete and a garden tool, a razor and any of a variety of wood planes/shavers/scrapers, a slingshot (it's not what you think it is) and a rubber band, a spring stick and a collapsible baton of a certain vintage, metal knucks and grain flails, a blackjack and a keychain with a monkey's paw, or a pocket knife [I know, not listed] and a butter knife as any weapon of like kind.
Thank you for your last questio - it's actually fairly easy to answer. Go to http://www.municode.com/Library . Play with several search phrases just to make sure you have not missed something. Also remember not all jurisdictions have ordinances, or the same length restrictions if they do have ordinances.
A question for you, if I may? What brought you to OCDO to ask about the concealed carry of stuff?