The chaffinch was described by the Swedish naturalist Carl Linnaeus in 1758 in the 10th edition of his Systema Naturae under its current binomial name. Fringilla is the Latin word for a finch, while caelebs means unmarried or single. Linnaeus remarked that during the Swedish winter, only the female birds migrated south through Belgium to Italy.
The English name comes from the Old English ceaffinc, where ceaf is "chaff" and finc "finch". Chaffinches were likely given this name because after farmers thresh their crops, these birds sometimes spend weeks picking through heaps of discarded chaff for grain. The chaffinch is one of the many birds depicted in the marginal decoration of the 15th century English illuminated manuscript the Sherborne Missal. The English naturalist William Turner described the chaffinch in his book on birds published in 1544. Although the text is in Latin, Turner gives the English name as chaffinche and lists two folk names: sheld-appel and spink. The word sheld is a dialectal word meaning pied or multicoloured (as in shelduck). Appel may be related to Alp, an obsolete word for a bullfinch. The name spink is probably derived from the bird's call note. The names spink and shell apple are among the many folk names listed for the chaffinch by Reverend Charles Swainson in his Provincial Names and Folk Lore of British Birds (1885).
The Fringillidae are all seed-eaters with stout conical bills. They have similar skull morphologies, nine large primaries, 12 tail feathers and no crop. In all species, the female builds the nest, incubates the eggs, and broods the young. Finches are divided into two subfamilies, the Carduelinae, containing around 28 genera with 141 species and the Fringillinae containing a single genus, Fringilla, with three species: the chaffinch (F. coelebs), the Tenerife blue chaffinch (F. teydea), and the brambling (F. montifringilla). Fringilline finches raise their young almost entirely on arthropods, while the cardueline finches raise their young on regurgitated seeds.
A number of subspecies of the chaffinch have been described based principally on the differences in the pattern and colour of the adult male plumage. Subspecies can be divided into three groups: the "coelebs group" that occurs in Europe and Asia, the "spondiogenys group" in North Africa, and the "canariensis group" on the Canary Islands. The subspecies from Madeira and the Azores are placed either in the "canariensis group" or in the "spondiogenys group". Genetic studies indicate that members of the "coelebs group" and the "spondiogenys group" are more closely related to each other than they are to members of the "canariensis group".
Within the "spondiogenys group", the gradual clinal variation over the large geographic range and the extensive intergradation means that the geographical limits and acceptance of the various subspecies varies between authorities. The International Ornithologists' Union lists 11 subspecies from this group, whereas Peter Clement in the Handbook of Birds of the World lists seven and considers the features of the subspecies balearica (Mallorca), caucasica (southern Caucasus), schiebeli (southern Greece, Crete and western Turkey), and tyrrhenica (Corsica) to fall within the variation of the nominate subspecies. He also suggests that the subspecies alexandrovi, sarda, solomkoi, and syriaca may represent variations of the nominate subspecies.
The authors of a 2009 molecular phylogenetic study on the three subspecies that are currently recognised on the Canary Islands concluded that they are sufficiently distinct in both genotype and phenotype to be considered as separate species within the genus Fringilla. They also proposed a revised distribution of subspecies on the islands in which the birds on La Palma (palmae) and El Hierro (ombrioso) are grouped together as a single subspecies while the current canariensis subspecies is split into two with one subspecies occurring only on Gran Canaria and the other on La Gomera and Tenerife.
- coelebs group
- F. c. alexandrovi Zarudny, 1916 – northern Iran
- F. c. caucasica Serebrovski, 1925 – Balkans and northern Greece to northern Turkey, central and eastern Caucasus and northwestern Iran
- F. c. coelebs Linnaeus, 1758 (nominate subspecies) – Eurasia, from western Europe and Asia Minor to Siberia
- F. c. balearica von Jordans, 1923 – Iberian Peninsula and the Balearic Islands
- F. c. gengleri O. Kleinschmidt, 1909 – British Isles
- F. c. sarda Rapine, 1925 – Sardinia
- F. c. schiebeli Erwin Stresemann, 1925 – southern Greece, Crete and western Turkey
- F. c. solomkoi Menzbier & Sushkin, 1913 – Crimean Peninsula and southwestern Caucasus
- F. c. syriaca J. M. Harrisson, 1945 – Cyprus, southeastern Turkey to northern Iran and Jordan
- F. c. transcaspia Zarudny, 1916 – northeastern Iran and southwestern Turkmenistan
- F. c. tyrrhenica Schiebel, 1910 – Corsica
- spondiogenys group
- F. c. africana J. Levaillant, 1850 – Morocco to northwestern Tunisia, northeastern Libya
- F. c. spodiogenys Bonaparte, 1841 – Eastern Tunisia and northwestern Libya: Atlas chaffinch
- canariensis group