Language Of Confusion: Ak-!, Part II

This week, more from the Proto Indo European root word ak-, meaning to be sharp, rise to a point, or pierce. Everything here has a lot of points!
 
The first word we’re looking at is acme, like the highest point of something. It showed up in the mid sixteenth century from the Greek akme, and of course the ak is from ak-, because high things often rise to a point. Amusingly enough, in English, people continued to write it in Greek letters until the seventeenth century. For some reason. And you know what very similarly spelled word is from the same place? Acne. It didn’t show up until 1813, from the Latin acne, from the Greek akmas, which is also from akme. I guess acne is “points” on someone’s face.
 
Next in sharpness is acuity. It showed up in the early fifteenth century, a little before acumen. It’s from the Old French acuite and Medieval Latin acuitatem, from the classical Latin verb acuere, to sharpen, which is also where acumen comes from. If your perception is sharp, you have acuity.
 
Now for a word that will make you go “Oh, yeah, that makes sense.” Acupuncture first showed up in the late seventeenth century meaning a surgical operation to ease pain. The acu- comes from the classical Latin acus, needle, because it and acupressure (which showed up in 1859) were what they called a method of pinning or wiring an artery shut, presumably with a nice, sharp needle. For some reason, in 1958, people started using those terms to mean the body-needle pressure method imported from Asia.
 
Finally today, we’re actually going to look at a prefix, acro-, which is the start of words like acronym, acropolis, and acrylic. It comes from the Greek akro-, pertaining to an end or extreme, from akros, which means extremely in both a literal or figurative sense and is from ak-. An acropolis is an elevated part of a city, an acronym takes the first letter of each word, and acrylic… well, it was named for the substance in garlic and onions that makes people tear up (i.e. is sharp). Acro- means high, first, extreme.
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at Austin Linguistic Research Center
University of Texas at San Antonio’s page on Proto Indo European language
Dictionary of Medieval Latin