conch / conk 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. 👇
conch: (noun) any of various edible tropical marine gastropods of the genus Strombus having a brightly-colored spiral shell with large outer lip.
conk: (noun) informal term for the nose. (verb) hit, especially on the head.
conch: k·AA·n·ch
conk: k·AA·ng·k
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)