the whole L2/"layer" tag is defunct/redundant

its not like most subnetworks remain layers that only wrap around a core network and function solely to secure the enclosed value of that one mainnet.. instead many are subnetworks that bridge between multiple mainnets so thats why the community prefer words like subnetworks and bridges (think subways and highways and bridges with on and off ramps)

the terminology of analogies is not fixed but the "layer" term is getting less and less relevance when most subnetworks start offering access to different currencies and no long just wrap around and function with one network

as for the definition of subnetworks. is similar/akin to subdomains and also illustrating the analogy that these subnetworks are below the mainnet in terms of security. as many subnetworks will never be as secure as the mainnet, thus a subclass of network security, rather than the illusion/delusion of top quality penthouse, top security, leader, subliminal word garbage done for fame stealing and false promising