feature: a prominent attribute or aspect of something
abstraction: a general concept formed by extracting common features from specific examples
superclass myriapoda: used in some classifications to encompass the millipedes (Diplopoda) and centipedes (Chilopoda); formerly a large taxon including also the Pauropoda and Symphyla; the term Myriapoda now usually used synonymously with Diplopoda and limited to the millipedes