Even many musicians haven't heard of figured bass. Also called basso continuo, a simple explanation of the term is a short way to note chords on a musical score. If you have never heard of it, it's most likely because the method isn't used today. However, it could be considered akin to, or a precursor of, a modern chord chart.

Figured bass originated in the Baroque era of the17th and 18th century. Music has evolved over the centuries and still does today. The development of figured bass came in response to one of these early musical style evolutions. The Baroque music period came on the heels of the Renaissance period. Music from the Renaissance was generally characterized by its reliance upon intervals of thirds. Of course, musical trends evolve over a period of time. For this reason, it's difficult to pinpoint an exact year when this trend shifted. Usually a new musical era is well under way before anyone realizes there has been a change. Modal characteristics of Renaissance music eventually gave way to more tonal music. The defining characteristic of tonal music is its use of fifths. This is in contrast to the previous intervals of thirds. This led the way for Baroque style music.

Composers and musicians in this period began using more elaborate instrumentation during the Baroque period. New musical instruments were being developed that contributed to the trend. Many of them had wider range capabilities, allowing for more variety in musical scores. New playing techniques were also developed, lending a distinction to music of this period such as had not previously been heard.

The more complex nature of Baroque music made a new form of musical notation a necessity. This is how figured bass was born. Playing music by reading figured bass required more than rudimentary musical skills. With this method, the melody line and the bass line are noted on a traditional musical scale (bass clef and treble clef). The instrumentalist(s) would fill in the harmony lines based on the bass note. The harmony part, or the part that was implied but not written in the score, was known as the continuo.

To play figured bass, it is necessary to have a working understanding of chords. An instrumentalist reading a score with figured bass would see the melody notes and the bass notes. The instrumentalist would assume that the continuo notes that would accompany would be a standard fifth interval unless otherwise noted. If another variation was desired, numbers would appear on the score underneath the bass note indicating the appropriate interval.

Like many trends, the use of the figured bass method became obsolete. Today, chords are often indicated by abbreviating their names (i.e.,"C7" for a C major/minor seventh chord). Similar to figured bass, instrumentalists have some leeway for improvisation with this type of musical annotation. This is in contrast to music that has every note for each part annotated on a musical staff. Like shorthand once was to writing, so was figured bass to music. And like shorthand, changes in technology and trends have greatly diminished the use of figured bass.