flatland \ˈ ̷ ̷ˌ ̷ ̷\noun 1. a.: land that lacks significant variation in elevation < the farm includes a valuable stretch of flatland along the river > b.: a region in which the land is predominantly flat — usually used in plural < coastal flatlands > 2.: a hypothetical two-dimensional world • flat·land·er\-də(r)\noun-s