The Italian and more original term ‘basso continuo’ has now largely replaced ‘thoroughbass’ as (1) the English term for the art of accompaniment from a figured bass line, and (2) the name or label for such a bass line when issued as an instrumental part. It is uncertain when the term originated. Early treatises used other terms (e.g. M. Locke: Melothesia, or Certain General Rules for Playing upon a Continued-Bass, 1673; i.e. a Restoration equivalent of the French basse continue), though John Blow’s Rules for Playing of a Through Bass (MS, GB-Lbl Add.34072) show the 17th-century identity of ‘thorough’ and ‘through’ as equivalents of continuo. For the instrumental part itself, particularly of the Italianate sonatas, etc, published in London from the end of the 17th century onwards, ‘basso’, ‘per l’organo’, ‘cimbalo’ and other names are as likely as ‘thoroughbass’. Like Generalbass, the term came to stand for the science of harmony in general; and like the word Continuo, it probably arose as a description of a bass part present all or most of the time throughout a composition, unlike optional or obbligato parts.
PETER WILLIAMS/DAVID LEDBETTER