Device that connects multiple networks? Layer 3 of the OSI model? Consumer ones tend to have more than that, but the more specific definition would work fine.

Yeah conceivably you could use this to ban any network device that is capable of routing between interfaces, so lots of switches with new firmware could do it, often terribly, as well as PCs with multiple interfaces. But its probably going to involve intention.

The definition is at the bottom of this document https://www.fcc.gov/sites/default/files/NSD-Routers0326.pdf

...which in turn refers to https://nvlpubs.nist.gov/nistpubs/ir/2024/NIST.IR.8425A.pdf

Good question for devices that ship with multiple network interfaces, multiple video outputs, no RAM and no software.