Wikipedia
Alberti bass is a particular kind of accompaniment figure in music, often used in the Classical era, and sometimes the Romantic era. It was named after Domenico Alberti (1710–1740), who used it extensively, although he was not the first to use it.
Alberti bass is a kind of broken chord or arpeggiated accompaniment, where the notes of the chord are presented in the order lowest, highest, middle, highest. This pattern is then repeated. The broken chord pattern helps to create a smooth, sustained, flowing sound on the piano.
Alberti bass is usually found in the left hand of pieces for keyboard instruments, especially for Mozart's piano pieces. However, it is also found in pieces for other instruments.
Well-known examples of Alberti bass include the beginning of Mozart's Piano Sonata, K 545. A famous example from 20th-century American popular music is the rhythm guitar part of the 1962 "surf rock" standard " Pipeline", by The Chantays.