Inventions is a title that Bach uses in his foreword to the collection of this work. It is adapted from the theory of rhetoric. The inventions used by Bach means clearly that he first shows an invented motif and develops of this simple figure an entire (but short) composition:
"Straightforward Instruction, in which amateurs of the keyboard, and especially the eager ones, are shown a clear way not only (1) of learning to play cleanly in two voices, but also, after further progress, (2) of dealing correctly and satisfactorily with three obbligato parts; at the same time not only getting good inventiones, but developing the same satisfactorily, and above all arriving at a cantabile manner in playing, all the while acquiring a strong foretaste of composition."
Title and historical background of inventiones:
Traditionally, this concept of 'invention' denoted an important stage in composition; it originated from a famous Roman orator, Marcus T. Cicero's rhetoric, which was still widely studied in the 18th-century Germany:
In his De Inventione, Cicero listed five stages in creating an oration, namely invention (inventio), arrangement (dispositio), style (elocutio), memory (memoria) and delivery (pronuntiatio). He explains, 'one must first hit upon what to say; then manage and marshal his discoveries, not merely in orderly fashion, but with a discriminating eye for the exact weight, as it were, of each argument; next go on to array them in the adornments of style; after that keep them guarded in his memory; and in the end deliver them with effect and charm.'