we'd need a expert on cephlapods to explain how squids and cuttle fish differ.

squids, cuttlefish and octopus are all members of the same family.

squids and octopus have 'hard,bony beaks' at their mouths, and squids and cuttle fish have a small hard plate (not bone, but hard) that gives their body's some shape (the shape of this hard plate is sort of a flattened cone.)

almost all of them are edible, and the sizes vary from very small (palm of the hand size) to 6 or more feet long!

i think, like many 'common names', there is overlap (what one group calls a cuttle fish, another group might call a squid.

(i think of shrimp/prawns/crawfish... i don't think there is a real difference between shrimp and prawns-i think they are different names for the same animal. (even if both shrimp and prawns are used in an area) one man's jumbo shrimp is another man's prawn.