Prose
The word "prose" first appears in English in the 14th century. It is derived from the Old French "prose", which in turn originates in the Latin expression "prosa oratio" (literally, straightforward or direct speech).
Motet
In the early 20th century, it was generally believed the name came from the Latin "movere", ("to move"), though a derivation from the French "mot" ("word", or "phrase"), had also been suggested. The Medieval Latin for "motet" is "motectum", and the Italian "mottetto" was also used. If the word is from Latin, the name describes the movement of the different voices against one another. Today, however, the French etymology is favoured by reference books, as the word "motet" in 13th-century French had the sense of "little word". In fact, the troped clausulas that were the forerunner of the motet were originally called "motelli" (from the French "mot", "word"), soon replaced by the term "moteti".