buffer: Neither buffer ‘fellow’ [18] nor buffer ‘shock absorber’ [19] can be traced back with any certainty to a source, but the likeliest conjecture is that they both come (independently) from an obsolete English verb buff, which was probably originally (like puff) imitative of the sound of blowing or breathing out. The earliest recorded sense of this, in the late 13th century, was ‘stammer’, and so the human buffer may originally have been a ‘stammerer’. By the 16th century we find the verb being used in the sense ‘make the sound of something soft being hit’, which is a likely source of buffer ‘shock absorber’.
