Wellll that's a bit like asking what's the difference between an automobile and a vehicle.... all automobiles are vehicles, but not all vehicles are automobiles. All plywoods are laminated wood, but not all laminated wood is 'plywood'.
One example of "laminated wood" and probably the most common, is laminated hardwood flooring. This is usually about 3/4" thick, and consists of 3 thick layers of wood. This is a common alternative to 'solid' wood....you can sand the floor down up to a quarter inch, if necessary, its more stable than solid wood, and costs less. (But its still more expensive than other forms of flooring, hehe).
Another example of laminated wood, is 2 ply veneers. Ive used some of these myself. Theyre 2 layers of veneer, running crosswise to each other, to add strength, and stability. But theyre still thinner than most greeting cards.
Plywood can come in many shapes sizes and forms.... usually we think of it in certain basic terms... 3, 5, or 7 layers, construction, exterior, or cabinet grade, etc. You can get it with specific veneers, like birch, or oak, or even in a 'bendable' form... literally, you can roll it in a tube ('Bendy' ply is the common name for this type... its 3 layers, and comes in two thickness options).
Another type that kind of blurs the lines between the two, is curved laminated shapes... for example, kitchen chairs...that top piece that runs across the back (many have a design embossed into them), is usually a laminated wood...it LOOKS a lot like plywood... but it is layed up in a bowed form, or mold, where plywood is generally a 'flat' product.
Perhaps you'd like to give a context to your question? We might be able to give some more specific details then.
Hope this helped