Q: I’m fascinated by the use of a word denoting a body part to characterize a person. For example, an expert in detecting different smells is known in the fragrance industry as a “nose.” And a smart person is commonly known as a “brain.” I’m wondering how this all came about.
A: We have a long tradition in English of referring to people as body parts. In fact, it almost seems that for every body part there’s a hidden (or not so hidden) noun meaning a person. We’ll skip the obscene ones, if you don’t mind!
Besides the usual meaning (one’s schnozz), “nose” has also meant the sense of smell, or the faculty for discriminating scents. It’s had that meaning since about the year 1375, according to the Oxford English Dictionary.
This use is probably what led to its becoming a slang term for a spy or informant, a meaning it has had since the late 18th century. And it also means “a person who creates, identifies, or judges fragrances, esp. in the perfume industry,” a meaning of “nose” since the late 1950s, the OED says.
A brainy person has been called “a brain” or “the brains” pretty regularly since 1914. But an earlier, figurative use meaning something more like “head” or “nerve center” was recorded in 1844, in Alexander W. Kinglake’s book Eothen: Or, Traces of Travel Brought Home From the East: “The accomplished Mysseri … was in fact the brain of our corps.”
The word “head” has been used to mean a person to whom others are subordinate since the late 9th century.
“Foot” was once used to mean a person traveling on foot (1200-1600s) or a foot soldier (1500-1800s).
Someone who lends a hand or works with his hands has been called a “hand” since 1590 (the same time the word was first used to mean a round of applause).
In Victorian times, a “leg” (short for “blackleg”) was a name for a swindler at a racetrack or other gambling venue, and in the mid-20th century “leg” was a slang term for a young woman of easy virtue.
Since 1382 the word “eye” has meant a person who uses his eyes on another’s behalf (hence the later term “private eye”).
From the mid-1500s until our own time, we’ve used the word “mouth” to refer to a consumer of food or a spokesperson. We’ve also called a big-mouthed person a “mouth” since the 1600s.
And since the late 19th century, the OED says, we’ve used “finger” as slang for “(a) a policeman or detective; (b) an informer; (c) a contemptible or eccentric person; (d) a pickpocket; (e) one who supplies information or indicates victims to criminals.”
A sympathetic person is called “a shoulder to cry on.” And for at least a century, we’ve called someone we depend on our “right arm.”
There are no doubt other examples that I’m missing, but you get the idea! It’s a long and honorable tradition.