Convergent evolution is a term used in biology to describe the process by which similar traits evolved independently, such as the evolution of wings in insects, birds, and bats. I personally like to use the phrase to describe more than just biology. For example, I think about how thin, round bread is prevalent in different cultures across the globe. Were these foods invented independently, or is there a “common ancestor” of tortillas, crepes, injera, and the like? (I’m sure the information is out there; I just haven’t researched it yet.)
In a lot of ways, the evolution of words is analogous to the evolution of life. As I mentioned in my previous post, similar words, like hack, hachet, and hash, can be traced back to a “common ancestor,” hache. Sometimes words appear similar but actually converged from independent paths, such as hash and hashish. I like to use the phrase convergent evolution to describe these instances. Today I will explore another example: lime.
The English word lime has two common meanings: the citrus fruit and the mineral. Why do I use the same word to describe what I squeeze on my tacos and what clogs up the little holes of my showerhead? Are these meanings related, and if not, how did they both arrive at the same word we use today?
The Citrus Fruit
Let’s start with the tastier of the two. The English word lime can be traced back to the 1630s, but the origin of the word is much older and has gone through many iterations. Wild limes originate from Indonesia and Malaysia and were brought to the Mediterranean region around 1000 CE. The believed etymological evolution of the citrus lime is as follows:
Malay limaw -> Persian limun -> Arabic lima -> Spanish lima / Portuguese limão -> English lime
The Mineral
I love researching etymology because there are always little “a-ha” moments. This time it was the discovery that lime is related to slime. Now, the connection may seem obvious because lime and slime look and sound very similar, but in my personal experience they reside in completely separate realms. When I think of lime I think of limestone or hard water, both of which connote something hard or rigid. Definitely not something slimy. However, the origin of both lime and slime is the Proto-Indo-European (PIE) root (s)lei- meaning “slimy, sticky, slippery.” This was a surprise to me, until I understood the historical uses of limestone.
Limestone is a rock made of the shells of tiny sea creatures. These shells are composed primarily of calcium carbonate. In fact, lime is used in the industrial sphere to refer to a wide range of inorganic materials containing calcium. Calcium carbonate is also responsible for hard water stains and the limescale that clogs up plumbing.
When limestone is heated, such as in a limekiln, a powder is formed that, when mixed with water, creates a sticky substance. This sticky substance historically formed the base of mortar before cheaper cement was invented. This explains lime’s sticky origin.
From the PIE root (s)lei- came the Proto-Germanic word leimaz, meaning “birdlime.” Birdlime is a sticky substance applied to twigs to catch small birds. The subsequent Old English word lim incorporated both the meanings of “birdlime” and “mortar or cement.” Lim eventually evolved into modern English lime.
In case you were wondering, slime came from Old English slim from Proto-Germanic slimaz, meaning “slime.” So, slime has always meant slime.
Convergent Evolution of Lime
To answer my original question, no, lime the fruit and lime the mineral do not share a common ancestor. Lime the fruit can be traced back to the Proto-Malayo-Polynesian (PMP) language, and even further back to the Proto-Austronesian (PAN) language, which is a separate language family than the Proto-Indo-European (PIE) language from which lime the mineral originates. Language families are used in historical linguistics to describe the evolution of languages over time, just as taxonomy is used to classify the evolutionary relationships of living things. Two disparate concepts – a sour, green fruit and a sticky calcium containing substance – converged onto one English word: lime.
Sources
https://www.etymonline.com/word/lime#etymonline_v_9529
https://www.etymonline.com/word/slime#etymonline_v_23676
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