An atomizer is anything that you screw onto your eGo battery or mod that has a tank for
juice and a coil in it and turns the
juice into vapor. A mod is pretty much a modified battery tube, or in some cases a box. A dripper is an atomizer (atty) that you drip a bit of juice into and vape for a few hits, and drip more into it, and vape for a few hits, etc. etc, etc. A clearomizer is one of those atomizers you can see the juice in that screws onto an eGo battery and has a coil in it that heats the juice when you push the button and turns it into vapor for you to get a hit on. In short it's another kind of atomizer.
An RBA is a ReBuildable Atomizer. and includes Genesis atomizers which are made to function with a stainless steel mesh wick wound with a kanthal or nichrome wire coil, and these generally are used on what is called a mechanical mod, or mech. Then there are Kayfun style RBA's that use silica wicks, or cotton. That brings us to RDA's, which are Rebuildable Dripping Atomizers, (drippers) which I've already described.
Then there are the regulated mods, (modified battery tubes with electronics in them) and these have LED displays that tell you how many hits you took, your GPS location, blood pressure, suggested lottery numbers, and what watts you are
vaping at.
This brings us to Mechanical Mods, (mechs) which you should not venture into without a fair amount of homework because they just put the power to your coil without bothersome electronics and LED menus, and just get it done, but you'd best know what you are doing with them before messing around with them or bad stuff can happen and result in severe post-vape cognitive dissonance.