Cyracuz wrote:It is my belief that the original meaning of "drop of water" was "water dropping". The other meanings have less logic to it. It is easy to assume that "drop" has anything to do with size
Water drops are fairly consistent in size because surface tension and gravity in combination allow a limited range of size for drops (which are forming on a surface and then falling off when their mass exceeds the surface tension).
Rain drops (which are spherical, not "drop" shaped) are limited in size mainly by air turbulence which exceeds surface tension at some point. Drops which formed in a vacuum and were allowed to accumulate would be virtually limitless in size.
But in the "real" world, a "drop" of water is a relatively common and consistant reference to size.