We are aware that those two words are sometimes used synonymously, or very nearly so.
"Witchcraft of New England Explained by Modern Spiritualism"
Allen Putnam
The two terms are now generally used synonymously.
"The Leper in England: with some account of English lazar-houses"
Robert Charles Hope
These terms seem to be used synonymously and the latter is used where messa di voce is meant.
"Sixty Years of California Song"
Margaret Blake-Alverson