colonel / kernel are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
colonel: (noun) a commissioned military officer in the United States Army or Air Force or Marines who ranks above a lieutenant colonel and below a brigadier general.
kernel: (noun) the inner and usually edible part of a seed or grain or nut or fruit stone. (noun) a single whole grain of a cereal. (noun) the choicest or most essential or most vital part of some idea or experience.
colonel: k·ER·n·ah·l
kernel: k·ER·n·ah·l
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)