In my thesis I am quoting a passage from a paper in which the author* used the word "learnable" in the sense of something that is easy to be learned.
I have searched for the word in both the Merriam-Webster and the Cambridge English online dictionaries, but didn't find it there. Nevertheless, this word seems to be used quite a lot in many scientific papers, it returns 775,000 results on Google and a lot of occurrences in Wikipedia.
So I ask: is this a valid word in English or, perhaps, just a neologism?
* he is from the University of South Florida and has a common American name - just in case somebody finds this relevant