Caving

Caving is geology, rope technique and timekeeping in the same afternoon, and the vocabulary comes from all three. The word to stop at is el desarrollo, in el desarrollo total de la cueva, which is the surveyed length of everything a cave contains — not its depth and not its size, but the sum of the passages laid end to end. Desarrollar is to unroll, and the noun follows the image wherever it goes. It is « development » in the ordinary sense, el desarrollo económico. It is the working-out of a calculation, el desarrollo del ejercicio, which a teacher marks even when the answer is wrong. On a bicycle it is the gear — un desarrollo corto para subir — because the gear says how far one turn of the pedals unrolls along the road. English has no thread joining those, and has to change words four times.