Is it ensure, insure, or assure?
gram calorie n.
The Cambridge Phoenix equivalent of troff. So called because all Cambridge utilities were named after birds, GCAL was a "run off" equivalent, and Geococcyx californianus is the Latin name of the roadrunner. GCAL was eventually obsoleted by TeX.
It is believed that even more obscure puns lurked in the depths of Phoenix. Perhaps it is better they stayed there.