Wow, this is fascinating, Father Steve! Here's what Merriam-Webster Online Dictionary has:
Main Entry: man·do·lin
Pronunciation: "man-d&-'lin, 'man-d&l-&n
Variant(s): also man·do·line /"man-d&-'lEn, 'man-d&l-&n/
Function: noun
Etymology: Italian mandolino, diminutive of mandola
1 : a musical instrument of the lute family that has a usually pear-shaped body and fretted neck and four to six pairs of strings
2 usually mandoline [French, from Italian mandolino mandolin] : a kitchen utensil with a blade for slicing and shredding

A-HA! Take a look!
History of the Mandoline

At the very beginning, the slicer was not yet called the mandoline. But it without any doubt has very old origins. Effectively the first illustrated culinary book was published in 1570 by Bartolomeo Scappi who was pope Pius VIs cook. One of his books illustrations shows a small board with a central cutting blade and with other small perpendicular blades to cut vegetables into thin sticks. We are not able to give an exact date but, given the details of the drawings, such a slicer had probably existed for a long time. The musical instrument, the Mandoline, was created in Italy near Naples. Its ancestor, called the "Mandorre" was an instrument with stiff strings.

This name was probably used for the cooking instrument before the Second World War. However, it was well-known from 1949. Then, Mr Jean BRON, a man from "Haute-Savoie" born in Morzine, made the first metal version. In this way, a wooden vegetable slicer invented by Mr Marcel Forelle, from Toulouse in the south of France, in 1930 was modernized.

The cooking instrument was given the name of the musical one because cooks "play" their mandoline in the same way as musicians. It is often said that at the beginning, the mandoline didn't have a folding stand. The cook simply held it pressed against his chest to slice the vegetables directly above the dish.

It is interesting to notice that in professional cooking, other equipment takes the name of musical instruments such as the piano and the guitar.
This came from a commercial site; but if you want to see for yourself, it's:
http://www.simply-natural.biz/Bron-Coucke-Professional-Mandoline.php