Usually the protocol stack is PHY/MAC/IP/TCP/TLS/application which is 6 layers. It's the same as the OSI stack except for the lack of a session layer, which is somewhat split between TCP 3-way handshake and TLS authentication/authorization.
TCP and IP exist as part of the Internet stack. The OSI stack consisted of an alternate set of standards (like LAPB and X.400) which were not widely adopted.
Even if you map Internet protocols to the OSI model -- which is imprecise at best -- TCP represents the transport layer, and IP the network layer. They're not a single component.
You made me stop and question myself for a second, but this definitely isn't right. Usually when people talk about "TCP/IP" it's shorthand for the whole "Internet Protocol Suite", but even naively TCP and IP are two different layers.
Yep, the slash is meaningful. I think of writing "TCP/IP" that way as in a fraction -- "TCP over IP" or "TCP on IP". At least, that was how my brain learned it.