costeanEtymologyPresumably from Cornish kodha (“to fall, happen”) + sten (“tin”).costean means A trench in solid rock intersected by pits which reveals mineral veins. Lexicurio rates it Sui generis — a strength score of 87 out of 100.nounA trench in solid rock intersected by pits which reveals mineral veins.verbTo search for lodes by sinking small pits through the superficial deposits to the solid rock, and then driving from one pit to another across the direction of the vein, so as to cross all the veins between the two pits.