The log which, if removed, would free up the wholelogjam.
The key issue or problem, which if (re)solved, would make the current task easy to complete. The issue around which the whole problem revolves.
1932 December, Homer L. Dodge, “The Improvement of College Teaching”, inThe Journal of Higher Education, volume 3, number 9, Ohio State University Press,page485:
In a log jam, where everything is at cross-purposes, there is somewhere a key log causing the trouble. Thekey log in the educational jam is the department, and the things which have caused it to make so much trouble are narrow departmental ambition and excessive striving for reputation through the publication of research.
1938, Col. Leonard P. Ayres, quoted in ""Cheapskate" Counterpoint", inTime magazine, Monday, Jan. 10, 1938
Present conditions are "a crisis of confidence. . . . Electric utilities are thekey log."
