Mitochondrial DNA studies suggest that speciation in the genus occurred during the Pleistocene and earlier, while other evidence suggests speciation occurred 25,000 to 15,000 years ago.
Most Passer species are dull-coloured birds with short, square tails and stubby, conical beaks, between 11 and 18 cm (4.3 and 7.1 in) long.
The genus Passer contains about 25 species, depending on the authority, 26 according to the Handbook of the Birds of the World.
Dialectal names include sparr, sparrer, spadger, spadgick, and philip, mainly in southern England; spug and spuggy, mainly in northern England; spur and sprig, mainly in Scotland; and spatzie or spotsie, from the German Spatz, in North America.
The house sparrow is also called by a number of alternative English names, including English sparrow, chiefly in North America; and Indian sparrow or Indian house sparrow, for the birds of the Indian subcontinent and Central Asia.
The Latin word domesticus means "belonging to the house", like the common name a reference to its association with humans.
The Latin word passer, like the English word "sparrow", is a term for small active birds, coming from a root word referring to speed.
Later, the genus name Fringilla came to be used only for the common chaffinch and its relatives, and the house sparrow has usually been placed in the genus Passer created by French zoologist Mathurin Jacques Brisson in 1760.
It was described from a type specimen collected in Sweden, with the name Fringilla domestica.
