colonel / kernel [ˈkɜrnəl]
colonel – n. – an officer of land or air forces junior to a brigadier but senior to a lieutenant colonel
kernel – n. – 1. the edible central part of a seed, nut, or fruit within the shell or stone; 2. the grain of a cereal, especially wheat, consisting of the seed in a hard shell; 3. the central or essential part of something (even intangible, as in an argument)