One of those questions for which there is no search engine incantation. Jon
I also looked in the Oxford English Dictionary for etymology. It has:4. The memory organ
4.1. Ideally one would desire an indefinitely large memory capacity such that any particular aggregate of 40 binary digits, or word (cf. 2.3), would be immediately available-i.e. in a time which is somewhat or considerably shorter than the operation time of a fast electronic multiplier.
Dan Hd. Computing. A consecutive string of bits (now typically 16, 32, or 64, but formerly fewer) that can be transferred and stored as a unit.machine word: see machine word n. at machine n. Compounds 2.
1946 H. H. Goldstine & J. Von Neumann in J. von Neumann Coll. Wks. (1963) V. 28 In ‘writing’ a word into the memory, it is similarly not only the time effectively consumed in ‘writing’ which matters, but also the time needed to ‘find’ the specified location in the memory.
[plus newer citations]