Flatten

Flatten may refer to:
 * Amy Flatten, American expert on international scientific collaboration and abstract oil painter
 * Flat-ten engine, an engine with two banks of five opposing cylinders each
 * Svein Flåtten, Norwegian politician
 * Mount Flatten, mountain in the animated television series The Rocky and Bullwinkle Show
 * Flattening, the compression of a circle or sphere into an ellipse or an ellipsoid
 * Flattening of affect, loss or lack of emotional expressiveness
 * Flattening the curve, a technique to slow spread of a pathogen in order to minimize peak demand on healthcare resources
 * Regrading, changing the slope or grade of land; levelling
 * Flat-file database, a database file format where there are no structures for indexing or recognizing relationships between records; flattened