A doll is a model of a human (often a baby), a humanoid, an animal or a fictional character (like a Troll or a Smurf). The model is usually a miniature, but a baby doll may be of true size. A large model of hard material is called a statue.
Dolls are distinguished from action figures, which are generally of plastic construction and poseable to some extent, and exist largely for the purpose of marketing the television shows or films which feature the characters they are often modeled after.

Some dolls are intended as toys for children, usually girls, to play with. The first dolls known to have been commercially produced as children's playthings were made in Germany in the early 15th century in factories at Nürnberg, Augsburg, and Sonneberg. Production methods were crude; the products were made of wood, clay, rags, and wax and were dressed torepresent German women of the time.

Some dolls may be used for decoration or have some cultural significance, possibly for use in some ceremony or ritual. Since the Middle Ages (5th century to 15th century), the crèche, with its doll figures of the Holy Family, has been a part of Christmas observations in many parts of the world. The religious use of dolls or doll-like figures persists in other modern Christian observances. In Mexico, for example, dolls representing Our Lady of Guadalupe are ceremonially paraded. Fertility rites involving the kachina dolls of the Hopi people represent another continuation of ancient practice. These cottonwood or cactus-root figures are given to children but are regarded as sacred objects, not as toys. Hinamatsuri or Girls' Day, is the Doll Festival in Japan. On 3rd of March, people display dolls (hinaningyō) dressed in old-style kimonos. The custom of displaying dolls began during the Edo period. It is a celebration especially for girls, and is sometimes called the "Girl's Festival". Formerly, people believed the dolls possessed the power to contain bad spirits in their bodies, and would thus save the owner from dangerous encounters. The origin of Hinamatsuri is Hinanagashi (literally, "doll floating";) in which paper dolls are put into a boat and sent on a journey down a river into the sea, taking with them the bad spirits.

Ancient dolls, small figures, were most of the time religious objects. Dolls fashioned of flat pieces of wood, painted with geometric designs and with “hair” made of strings of clay or wooden beads, have been found in Egyptian graves dating from 3000 to 2000 bc. The presence of such dolls in children's tombs suggests that they were cherished possessions as well as cult objects, like the shawabtis, or tomb figures buried with adults to serve them in the afterworld. Dolls were also buried in Greek and Roman children's graves.

Most ancient dolls that were found in children's tombs were unpretentious, humble creations, made of common clay, rags, wood, or bone; better examples were fashioned of ivory, wax, or terra-cotta(a baked reddish-brown clay). Evidently the objective was to produce a lifelike image. Some dolls made as early as 600 bc had movable limbs and removable garments. In Greece, for instance, jointed dolls were found in temples dedicated to goddesses Demeter and Persephone. Such dolls were also found in Egyptian's temples.

Here is what Wikipedia has to say about voodoo dolls: Public relations-wise, Vodou has come to be associated in the popular mind with such phenomena as "zombies" and "voodoo dolls". While there is ethnobotanical evidence relating to "zombie" creation, it is a minor phenomenon within rural Haitian culture and not a part of the Vodou religion as such. Such things fall under the auspices of the "bokor" or sorcerer rather than the priest of the Lwa Gine. The practice of sticking pins in "voodoo dolls" has been used as a method of cursing an individual by some followers of what has come to be called "New Orleans Voodoo", which is a local variant of hoodoo. This practice is not unique to New Orleans "voodoo" however and has as much basis in European-based magical devices such as the "poppet" as the nkisi or bocio of West and Central Africa. In fact it has more basis in European traditions, as the nkisi or bocio figures used in Africa are in fact power objects, what in Haiti would be referred to as pwen, rather than magical surrogates for an intended target of sorcery whether for boon or for bane. Such "voodoo" dolls are not a feature of Haitian religion, although dolls intended for tourists may be found in the Iron Market in Port au Prince. The practice became closely associated with the Vodou religions in the public mind through the vehicle of horror movies. There is a practice in Haiti of nailing crude poppets with a discarded shoe on trees near the cemetery to act as messengers to the otherworld, which is very different in function from how poppets are portrayed as being used by "voodoo worshippers" in popular media and imagination, ie. for purposes of sympathetic magic towards another person. Another use of dolls in authentic Vodou practice is the incorporation of plastic doll babies in altars and objects used to represent or honor the spirits, or in pwen, which recalls the aforementioned use of bocio and nkisi figures in Africa. One Haitian artist particularly known for his unusual sacred constructions using doll parts is Pierrot Barra of Port au Prince.