Where does the term 'greased landing' come from?
I've always heard this referred to as a "greased landing" or a "greaser", but never a "greaser landing".

My understanding is that it is referring to a landing that was so good that somebody must have greased the entire runway so that you didn't even feel the airplane touch down.  If you've ever tried to pick something up that has been well greased, then you know what they are referring to.  It's very slippery and slides right out of your hands no matter how hard you try.