Of Muscles, Mussels, and Mice

The use of the word mouse to mean “computer device” began in 1965, but the appearance and movement of mice have influenced language for a long time.

The Latin word for “mouse” is mus. The Romans got the word from Greek mys. The word mussel,( “a bivalve mollusk”) derives from the Latin diminutive musculus (“little mouse.”) The little sea creature was thought to resemble a mouse in size and color.

The word and spelling muscle to denote contractile tissue dates from the late 14th century. The movement of a muscle, especially the one in the upper arm (biceps), can be compared to that of a mouse moving about under something. According to the Online Etymology Dictionary, the analogy of mouse/muscle already existed in Greek, and double-duty words that can mean either “mouse” or “muscle” exist in modern languages as well.

Old English spelled the word for the sea animal various ways: mucxle, muscell, muscelle, muscule, musscel, muxle. As might be expected, the spellings of mussel and muscle collided for a while. The spelling mussel to distinguish seafood from bodily tissue was first recorded about 1600, but the distinctive spelling was not fully established until the 1870s.

The prefixes my– and myo– that occur in many medical terms also derive from Greek mys:

myalgia: pain in a muscle or group of muscles.
myocarditis: inflammation of a a muscle layer of the heart
myoplasty: plastic surgery of muscular tissue.

The medical terms relate to the muscle connection, but mouse origins are clear in the word myomancy:”divination by interpreting the behavior of mice.”

Finally, just for fun, the Greek letter M is spelled and pronounced “mu” in English. The Greek vocative form of mys is also spelled “mu.” This is what happened when an English-speaking curate tried to teach his cat the Greek alphabet:

There was a kind curate of Kew
Who kept a large cat in the pew,
Which he taught every week
alphabetical Greek,

But got no farther than mu.*

*Thanks to Rod Decker