Rubs are usually dry.
Slathers are similar to rubs but wet
Sauces can be used for toppings or finishing
Mops/Sprits usually a sweet vinegar based liquid use to enhance bark and Flavor, some say it adds moisture
Basic dry Rub, used for adding flavor to the meat with some penetration
Slather like a rub but wet, Slather on the left
Slather
Mops, referred to as mops because many folks Mop this on with a little food mop.
Sprits/Spray Many use this as an alternative to a food mop.
Used for adding another dimension of flavor with minimal penetration
Sauce, Home made for Dipping, topping, finishing
Store Bought Sauce for Dipping, topping, finishing:
Marinade
Used for adding flavor and tenderizing some penetration.
Brine
Used for adding flavor, water content and tenderizing some penetration.
Getting Sauced!
Used more often than Mops/Sauces/Rubs/Slathers, etc...
I just threw this together its basic stuff and what I use each for,.
There is a whole science to this stuff and if you start diving into the scientific end, you will never have any time to enjoy "Q"-ing, hopefully I wont get pummeled on this post