fall line
n.— «Last month, Disney’s Buena Vista Games named Scott Novis vp and general manager of Fall Line (a snowboarding term meaning “the most direct path down the mountain”).» —“Wii Ambitions at Buena Vista Games” by Paul Hyman GameDaily BIZ Dec. 21, 2006. (source: Double-Tongued Dictionary)
Further reading
After our conversation about the expression dingle day, a term used by workers at a research station in Antarctica to denote bright, sunny weather, a listener offers a possible explanation for this term. It may derive from the idea of the skies...