cedar / ceder / seeder 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. 👇
cedar: (noun) any of numerous trees of the family Cupressaceae that resemble cedars. (noun) durable aromatic wood of any of numerous cedar trees; especially wood of the red cedar often used for cedar chests. (noun) any cedar of the genus Cedrus.
ceder: NA
seeder: (noun) a person who seeds clouds. (noun) a mechanical device that sows grass seed or grain evenly over the ground. (noun) a kitchen utensil that removes seeds from fruit.
cedar: s·IY·d·er
ceder: s·IY·d·er
seeder: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)