mechanism: device consisting of a piece of machinery; has moving parts that perform some function
object: a tangible and visible entity; an entity that can cast a shadow
commelinidae: one of four subclasses or superorders of Monocotyledones; comprises about 19,000 species in 25 families of mostly terrestrial herbs especially of moist places including: Cyperaceae; Gramineae; Bromeliaceae; and Zingiberaceae