Visible speech has 4 different meanings across 2 categories:
a phonetic alphabet invented by Melville Bell in the 19th century
spectrogram of speech; speech displayed spectrographically
A system of characters invented by Professor Alexander Melville Bell to represent all possible sounds, and intended to suggest the positions of the speech organs when uttering them.
An early phonetic alphabet, devised by Alexander Melville Bell in 1867.