Naismith's rule

/ (ˈneɪsmɪθs) /

noun

mountaineering a rule of thumb for calculating the time needed for a climbing expedition, allowing 1 hour for every 3 miles of distance plus 1 hour for every 2000 feet of height

Word Origin for Naismith's rule

C19: named after W. W. Naismith (1856–1935), Scottish climber, who formulated it