A dwarf was a term for a person of diminuative stature. On Earth, the term was most used in folk tales and myths to describe small, bearded people.
The word was later applied to science, where it was used to describe objects and effects with characteristics measurable as greatly less than a comparable counterpart. In astronomy, the fields of stellar classification and planetary classification use this as a descriptor for dwarf stars and dwarf planets, respectively. In biology, species can be named as such as well, such as the plant variety dwarf orange tree.