In my mother tongue, Japanese, there is only one word for that cephalopods with 10 legs (which probably isn't the right word): Ika （烏賊）.
Of course, there are many types of ika, but as a group, it is just called ika, while the cephalopods with 8 legs are tako （蛸）.
But in English, there are two words: squid and cuttlefish. I did not know the difference, apart from the vague notion that the squid relatively small and slim and the cuttlefish fat and thick, but Wikipedia explains to me that cuttlefish has cuttlebone, while squid doesn't. It sort of makes sense to me.
When I came to Greece, I thought cuttlefish is soupia and squid is kalamari and I could live happily for a while. And then, I was encountered by the third kind of 10 leg cephalopods called thrapsala (θράψαλα).
Thrapsala is very easy to find in supermarkets and fishmongers, I have never seen in restaurants. I looked up my Greek-Greek dictionary, but could not find the word. Hubby said he had never heard it.
It looks very much like what we call in Japanese Surume-ika and tastes like so, and the squid rings are also called thrapsala. If it is right, thrapsala is in squid family.
I asked Hubby's mum what is the difference betweeen thrapsala and kalamari and she said one has two longer legs and the other doesn't, but I am not really convinced.
Anyway, they are very cheap and sarakosti friendly. We will eat you a lot more, my dear thrapsala.