Typography and printing

Les points par pouce is the resolution figure, and the unit buried in it is worth stopping on. Le pouce is the thumb, and it is also the inch, because the inch began as the width of a thumb at the base of the nail. The same reasoning runs through the neighbouring languages: Spanish la pulgada is built on el pulgar, Portuguese a polegada on o polegar, and Italian il pollice has not even bothered to change its shape, since it is still the ordinary word for the thumb. English is the one language here that does not measure with the hand. « Inch » came into Old English from Latin uncia, a twelfth part, and a twelfth of a foot is exactly what an inch is. The curious thing is what became of the rest of that word: uncia was also a twelfth of the Roman pound, and in that sense it travelled again, later and through Old French, to land in English as « ounce ». So the inch on the ruler and the ounce on the scales are one Latin word borrowed twice, and neither has a thumb anywhere in it.