Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery (plural "potteries"). Pottery also refers to the art or craft of the potter or the manufacture of pottery.

The definition of pottery used by ASTM is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products." Some archaeologists use a different understanding by excluding ceramic objects such as figurines which are made by similar processes, materials and the same people but are not vessels.

Background - Pottery is made by forming the clay body into objects of a required shape and heating them to high temperatures in a kiln which removes all water from the clay, which induces reactions that lead to permanent changes including increasing their strength and hardening and setting their shape. Prior to some shaping processes, clay must be prepared. kneading helps to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed. This is called de-airing and can be accomplished by a machine called a vacuum pug or manually by wedging. Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it is shaped by a variety of techniques. After shaping it is dried and then fired.

Physical stages of clayClay takes on varying physical characteristics during the making of pottery.

Greenware refers to unfired objects. Clay bodies at this stage are in their most plastic form. They are soft and maleable. Hence they can be easily deformed by handling.
Leather-hard refers to a clay body that has been dried by exposing it to the air for a period of time. At this stage the clay object has approximately 15% moisture content. Clay bodies at this stage are very firm and only slightly pliable. Trimming and handle attachment often occurs at the leather-hard state.
Bisque refers to the clay after the object is shaped to the desired form and fired in the kiln for the first time, known ss "bisque fired". This firing changes the clay in the object in several ways. The clay hardens to a form that is no longer plastic. Mineral components of the clay will undergo chemical changes that will change the color of the clay.
Glaze fired is the final stage of some pottery making. A glaze may be applied to the bisque form and the object can be decorated in several ways. After this the object is "Glaze fired" at a very high temperature. This causes the glaze material to harden and causes the glaze and decoration to adhere to the object. The glaze firing may also harden the body still more as chemical processes continue to occur in the body.
In the making of earthenware, the object may be only "Once-fired" to create a glazed pot.

Bone-dry refers to Clay bodies when they reach a moisture content at or near 0%. This will occur after glaze firing, when that is done, or after bisque firing in the case of once-fired pottery.
Clays and mineral contentsThere are several earthen materials that are referred to as clay. Their properties of the clays differ in: Plasticity, the maleability of the body; porosity, the degree to which the fired pottery will absorb water; and shrinkage, the degree of reduction in size of a body as water is removed. The various clays also differ in the way in which they respond to different degrees of heat when fired in the kiln. Each of these different clays are composed of different types and amounts of minerals that determine the resulting pottery. There are wide regional variations in the properties of raw materials used for the production of pottery, and this can lead to wares that are unique in character to a locality. It is common for clays and other materials to be mixed to produce clay bodies suited to specific purposes. The two essential components of clay are Silica and Alumina which combine to form Aluminium silicate, also known as Kaolinite Following is a list of different types of clay used for pottery that are available in different regions of the world.

Kaolin This is sometimes referred to as China clay because it is used to make quality porcelain china. This is a form of pure clay which is 100% Kaolinite, free of any other mineral ccomponent.
Ball clay An extremely plastic, fine grained sedimentary clay, which may contain some organic matter. It is usually added to poreclain to incresase plasticity.
Fire clay A clay having a slightly higher percentage of fluxes than Kaolin, but usually quite plastic. It is highly heat resistant form of clay which can be combined with other clays to increase the firing temperature and may be used as an ingredient to make stoneware type bodies.
Stoneware clays Have many of the characteristics between Fire clay and ball clay, having finer grain, like ball clay but more heat resistant like fire clays.
Bentonite An extremely plastic clay which csn be added in small quantities to short clay to make it more plastic.
Common red clay and Shale clays have vegetable and Ferric oxide impurities which make them useful for bricks, but are generally unsatisfactory for pottery except under special conditions of a particular deposit.

Glazing
Glaze is a glassy coating on pottery, the primary purposes of which are decoration and protection. One important use of glaze is to render porous pottery vessels impermeable to water and other liquids. Glaze may be applied by dusting the unfired composition over the ware or by spraying, dipping, trailing or brushing on a thin slurry composed of the unfired glaze and water. The colour of a glaze before it has been fired may be significantly different than afterward. To prevent glazed wares sticking to kiln furniture during firing, either a small part of the object being fired (for example, the foot) is left unglazed or, alternatively, special refractory "spurs" are used as supports. These are removed and discarded after the firing.

Some specialised glazing techniques include: Salt-glazing, where common salt is introduced to the kiln during the firing process. The high temperatures cause the salt to volatize, depositing it on the surface of the ware to react with the body to form a sodium aluminosilicate glaze. In the 17th and 18th centuries, salt-glazing was used in the manufacture of domestic pottery. Now, except for use by some studio potters, the process is obsolete. The last large-scale application before its demise in the face of environmental clean air restrictions was in the production of salt-glazed sewer-pipes.
Ash glazing - ash from the combustion of plant matter has been used as the flux component of glazes. The source of the ash was generally the combustion waste from the fuelling of kilns although the potential of ash derived from arable crop wastes has been investigated. Ash glazes are of historical interest in the Far East although there are reports of small-scale use in other locations such as the Catawba Valley Pottery in the United States. They are now limited to small numbers of studio potters who value the unpredictability arising from the variable nature of the raw material.