means A metric unit of volume equal to one-thousandth of a liter, roughly the size of a single fat raindrop.

from A French coinage from the metric system born in the late 18th century, stitching together Latin 'mille' (thousand) as the shrinking prefix 'milli-' and 'liter,' itself from the older French 'litron' — a measure traced back through Medieval Latin to Greek 'litra,' a unit of weight. So the name literally announces itself as one-thousandth of a liter, no drama, just division.