The duim (meaning "thumb," but best translated as inch) was a unit of length in the old Dutch system of lengths. It was intended to be about the width of the top phalanx of the thumb of an adult man.
The length of the duim varied from place to place; Cardarelli gives the Amsterdam voet (which he calls "voeten," actually the plural form of the word) as 0.2830594 m = 11.1440709 in. = 0.9286726 ft , and the duim (which he calls "duime") as one twelfth of that, which would make it 0.02358828 m = 0.9286726 in. .
According to Wikipedia, the following were the lengths of some of the various duimen in use in the Netherlands prior to metrication:
- one Amsterdam inch (Amsterdamse duim) was 2.57393 cm = 1.013358 in. = 0.084447 ft .
- one Gelderland or Nijmegen inch (Gelderse of Nijmeegse duim) was 2.7 cm = 1.063 in. = 0.089 ft .
- one Rijnland inch (Rijnlandse duim) was 2.61 cm = 1.028 in. = 0.086 ft .