ducked / duct 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. 👇
ducked: (verb) to move (the head or body) quickly downwards or away. (verb) submerge or plunge suddenly.
duct: (noun) a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance. (noun) a continuous tube formed by a row of elongated cells lacking intervening end walls. (noun) an enclosed conduit for a fluid.
ducked: d·AH·k·t
duct: d·AH·k·t
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)