Pottery Glossary
New to pottery or brushing up on your ceramics knowledge? This glossary explains common pottery, clay, glaze, kiln and firing terms in simple language to help you feel more confident in the studio.
A
Absorption
The amount of water a fired clay body can absorb. Lower absorption usually means the clay has become more vitrified and less porous.
Alumina
A key ceramic material that helps stiffen glaze, improves durability and affects how a glaze melts and flows during firing.
B
Banding Wheel
A rotating platform used for decorating, carving, trimming or applying glaze evenly around a piece.
Bisque / Biscuit Firing
The first firing of clay. It turns greenware into a stronger, porous ceramic piece that is ready to glaze.
Bone Dry
Clay that has completely dried before firing. Bone dry clay is very fragile and contains no visible moisture.
C
Clay Body
A prepared clay mixture designed for a particular forming method, firing temperature, colour, texture or purpose.
Coiling
A hand-building technique where long rolls of clay are stacked and joined to create a form.
Cone
A pyrometric cone measures heat-work in a kiln. It helps indicate when the correct firing temperature and time have been reached.
Crazing
Fine crack lines in a glaze surface, usually caused by a mismatch between the clay body and glaze during cooling.
D
Dipping Glaze
A glaze mixed for dipping pottery pieces into the glaze bucket, often used for quick and even application.
Dry Foot
The unglazed base of a pot. This prevents glaze from sticking the piece to the kiln shelf during firing.
E
Earthenware
A low-fire clay body that remains more porous after firing. It is often used for terracotta, decorative ware and low-fire glazing.
Engobe
A coloured clay slip applied to leather-hard or dry clay for surface decoration.
F
Firing
The process of heating clay and glaze in a kiln to transform them into ceramic material.
Flux
A material that helps lower the melting point of glaze ingredients, allowing the glaze to mature during firing.
Food Safe
A term used for finished ceramic surfaces considered suitable for contact with food when correctly fired and used as intended.
G
Glaze
A glass-forming coating applied to ceramic ware. It can add colour, texture, decoration and surface protection.
Glaze Fit
The compatibility between a glaze and clay body. Poor glaze fit can cause crazing, shivering or other defects.
Greenware
Unfired clay work. Greenware can be soft, leather-hard, dry or bone dry before bisque firing.
Grog
Pre-fired clay particles added to clay bodies to improve strength, reduce shrinkage and add texture.
H
Hand Building
Creating pottery without a wheel, using techniques such as pinching, coiling, slab building and sculpting.
High Fire
A firing range commonly used for stoneware and porcelain, producing strong, vitrified ceramic ware.
K
Kiln
A specialised furnace used to fire clay and glaze at controlled temperatures.
Kiln Wash
A protective coating applied to kiln shelves to help prevent glaze from sticking permanently to the shelf.
L
Leather Hard
A stage where clay has firmed up but still contains moisture. It is ideal for trimming, carving and attaching handles.
Low Fire
A lower firing temperature range often used for earthenware clay and bright decorative glazes.
M
Mid Fire
A popular firing range for many studio potters, often around Cone 5–6. Many Decopot clay bodies and Abbots glazes are used in this range.
Maturing Temperature
The temperature range where a clay or glaze reaches its intended strength, surface and fired result.
O
Oxidation Firing
A firing atmosphere with enough oxygen, commonly used in electric kilns.
Overglaze
Decoration applied over an already glazed and fired surface, often requiring an additional lower-temperature firing.
P
Pinch Pot
A simple hand-building method where a ball of clay is shaped by pinching with the fingers.
Plasticity
The workability of clay. Highly plastic clay is easier to shape, stretch and form without cracking.
Porcelain
A fine, often white clay body known for its smooth surface, strength and sometimes translucency when fired thinly.
R
Reduction Firing
A firing atmosphere with limited oxygen, often used in fuel-burning kilns to create distinctive clay and glaze effects.
Raku
A fast-firing ceramic process where pieces are removed from the kiln while hot and often placed into combustible material.
S
Shivering
A glaze fault where small pieces of glaze flake off the clay body, usually caused by poor glaze fit.
Shrinkage
The reduction in size as clay dries and fires. Different clay bodies shrink at different rates.
Slab Building
A hand-building technique using flat sheets of clay to construct forms.
Slip
Liquid clay used for joining pieces, casting, decorating or surface treatment.
Stoneware
A durable clay body fired to mid or high temperatures. It is commonly used for functional pottery.
T
Throwing
The process of forming clay on a potter’s wheel.
Trimming
Removing excess clay from a leather-hard piece, often to shape the foot ring or refine the form.
U
Underglaze
A coloured decoration product applied before glazing. It is commonly used for painting, drawing and detailed ceramic design.
V
Vitrification
The process where clay becomes dense, strong and less porous during firing.
W
Wax Resist
A wax coating used to prevent glaze from sticking to certain areas, such as the base of a pot or decorative sections.
Wedging
Kneading clay to remove air pockets, even out moisture and prepare it for use.
Wheel Throwing
Shaping clay on a rotating potter’s wheel to create bowls, cups, vases and other forms.