Grounded conductor. In many wiring systems, the neutral conductor is intentionally connected to ground (earth). But not all systems are grounded, so you can have a neutral that isn't a grounded conductor. Take care you don't blithely use "grounded conductor" and "neutral" as synonyms or, in the field, treat them as such.
GFCI / AFCI. At one time, if you wanted a current trip device your only choice was a fuse. In many applications, a fuse is still an excellent choice. But, like a circuit breaker, it's an overcurrent device designed to protect wiring. It's not a current trip device to protect people. Although there are combo GFCI/AFCI devices on the market, only the GFCI function protects people from shock. An AFCI isn't a "better GFCI," it's a different device for a different purpose.
Identified. The particular device or electrical equipment is suitable for the intended use. Try to buy a "ground rod," and your electrical distributor/supplier won't sell you 10ft of schedule 80 pipe. The rod you get will be identified for that use via listing and/or labeling by a qualified product evaluation organization.