Apple stopped using the word 'laptop' because of the potential risk of using your laptop on your lap!
In 2006, Apple decided to stop using the word 'laptop' because potential injuries can ensue if your laptop is left on your lap for extended periods of time! Obviously, Apple made this switch in technical lingo for liability purposes, meaning nobody can sue them for using their laptop on their lap and getting a burn!
In fact, Apple switched the lingo in their manuals for the Macbook Pro and even advises users NOT to use their laptop on their lap! The Macbook Pro manual states "Do not leave the bottom of your MacBook Pro in contact with your lap or any surface of your body for extended periods. Prolonged contact with your body could cause discomfort and potentially a burn."
Apple, you sly company. For a whole article dedicated to why laptops are dangerous to use on your lap, click the source!