Is there a difference between a desktop computer hard drive and a laptop hard drive?

In other words, is it correct to say that if you are talking about an external hard drive with a USB connector. you can use it for either a desktop or laptop? Yes but no at the same time... Both of the Hard drives work exactly the same but the destop Drive(3.5") is larger than the Laptop hard drive.(Ranges between 1" and 2.5")