MIL-STD-31000B - A feature is a portion of an object defined by a procedure and controlled by parameters. Changing the parameters changes the feature dimensions. Examples of features include round holes, arbitrary cutouts, extrusions, volumes of revolution, sweeps, and lofts.

PTC - Any self-contained set of elements that can be defined and stored with the model and which has an impact on the geometry. A feature can be physical (hole, draft), procedural (for example, machining strategy in Expert Machinist), or computational (analysis). Features are listed on the Model Tree.