About the name 'ThinkPad'
Until 1992, IBM used to refer to their products only by numbers. This was also true for their notebooks manufactured until then and the tradition of those numbers has survived in the form of the type-and-model numbers, which every specific IBM product is still referenced more precisely than by its common name.
Rumor has it that Denny Wainwright of IBM intended to give the designation 'ThinkPad' to their pen-based computer 2521, which became the 700T. But then they decided to extend the use of the name to their laptops and hence the first ThinkPads hitting the market in 1992 were the 300, 700, 700C, and the aforementioned pen-based tablet 700T.
The ThinkPad name itself was inspired by the leather-bound pocket notepads issued to all IBM employees with the corporate motto 'Think' embossed on the cover. The combination of Think and NotePad lead to the name ThinkPad. IBM's corporate naming team was initially against the idea of using the ThinkPad name, since all previous IBM computers were referred to by model numbers rather than names. However, the popularity of the ThinkPad brand with the press convinced IBM to retain the name.