Solid-body

A solid-body musical instrument is a string instrument such as a guitar, bass or violin built without its normal sound box and relying on an electric pickup system to directly receive the vibrations of the strings.

Solid-body instruments are preferred in situations where acoustic feedback may otherwise be a problem and are inherently both less expensive to build and more rugged than acoustic electric instruments.

The most well-known solid body instruments are the electric guitar and electric bass. These were instrumental in creating new genres of music such as rock and heavy metal. Common woods used in the construction of solid body instruments are ash, alder, maple, mahogany, korina, spruce, rosewood, and ebony. The first two make up the majority of solid body electric guitars.

Solid body instruments have some of the same features as acoustic string instruments. Like a typical string instrument they have a neck with tuners for the strings, a bridge and a fingerboard (or fretboard). The fretboard is a piece of wood placed on the top surface of the neck, extending from the head to the body. The strings run above the fingerboard. Some fingerboards have frets or bars which the strings are pressed against. This allows musicians to stop the string in the same place. Ebony, rosewood and maple are commonly used to make the fingerboard. Some electric guitar necks do not have a separate piece of wood for the fingerboard surface. All the solid bodies have variations in scale length or, the length of the strings from the nut to the bridge. The action, or the height of the strings from the fingerboard, is adjustable on solid body instruments. Most solid bodies have controls for volume and tone. Some have an electronic preamplifier with equalization for low, middle, and high frequencies. These are used to shape the sound along with the aid of the main amplifier. Amplifiers allow solid body instruments to be heard at high volumes when desired.

...
Wikipedia