A binary file is a possibly non-text file such as images, videos or zips... anything could be read as a binary. Compiled code is another example of this. A binary file is anything a Computer could interpret and you by just reading it cannot. myascension.org -- Note: You could cast a text file as a binary too, if you want.
Binary can not be read by a human because there are too many trillions of possibilities to be discerned by a human, one would also need a starting point and if you started in the middle there would be no frame of reference