I realize this probably seems a bit more confusing externally, but from my perspective it's best to think about the use case of the item. We have a software module called 'Laserfiche WebLink' (and that's why all internal components like virtual directories and such say WebLink) that handles a couple different use cases. One of those use cases is specifically licensed as 'Public Portal', and covers external public anonymous read-only access. That was initially a specific license module, and in self-hosted, you can use (the application) Laserfiche WebLink either through that Public Portal licensing model, or without it. 

As Laserfiche Cloud only supports the Public Portal use case/model, it inherited just that aspect of the name. 

So basically, in all cases WebLink is the 'application, or piece of software', that has a specifically licensed use case called 'Public Portal'. In Laserfiche Cloud we use 'Public Portal' as the external module name since that's the use case offered there.