A forge is a type of hearth used for heating metals, or the workplace (smithy) where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature at which it becomes easier to shape by forging, or to the point at which work hardening no longer occurs. The metal is transported to and from the forge using tongs, which are also used to hold the workpiece on the smithy's anvil while the smith works it with a hammer. Sometimes, such as when hardening steel or cooling the work so that it may be handled with bare hands, the workpiece is transported to the slack tub, which rapidly cools the workpiece in a large body of water. However, depending on the metal type, it may require an oil quench or a salt brine instead; many metals require more than plain water hardening. The slack tub also provides water to control the fire in the forge.

A hearth is the place in a home where a fire is or was traditionally kept for home heating and for cooking, usually constituted by at least a horizontal hearthstone and often enclosed to varying degrees by any combination of reredos, fireplace, oven, smoke hood, or chimney. Hearths are usually composed of masonry such as brick or stone. For centuries, the hearth was such an integral part of a home, usually its central and most important feature, that the concept has been generalized to refer to a homeplace or household, as in the terms "hearth and home" and "keep the home fires burning". In the modern era, since the advent of central heating, hearths are usually less central to most people's daily life because the heating of the home is instead done by a furnace or a heating stove, and cooking is instead done with a kitchen stove/range alongside other home appliances; thus many homes built in the 20th and 21st centuries do not have hearths. Nonetheless, many homes still have hearths, which still help serve the purposes of warmth, cooking, and comfort.