I try and use "application layer" and "transport layer" myself but find that people don't really understand what I mean but for some reason understand "layer 4"

I try and use "application layer" and "transport layer" myself but find that people don't really understand what I mean but for some reason understand "layer 4" and "layer 7" (and sadly yeah, occasionally "layer 3".) I still insist in documents in using descriptive layer names but usually in conversation just refer to load balancers or proxies.