Language Of Confusion: Meter, Part I

Boy, does this word show up in a lot of places.
 
All versions of meter, whether poetic or a unit of distance, ultimately come from the same place, though interestingly, it seems like the poetic meter is actually the first version to show up in English sometime around the fourteenth century, while the unit didn’t appear until the eighteenth century. The words come from the classical Latin metrum, which means meter in the sense of measure, from the Greek metron, which is traced back to the Proto Indo European me-, to measure. So a meter is a measure. And though you might think that mete is somehow related, no, it’s not even a little.
 
What is related is any word that ends in -meter or -metry. The former means an instrument for measuring—so a thermometer is an instrument for measuring temperature, a barometer for measuring pressure—while the latter means process of measuring. Geometry, for example, is -metry plus Gaia of all things, making geometry literally the process of measuring land. Similarly, symmetry, which showed up in the mid sixteenth century, is from the Latin symmetria, where the syn- means together and the rest is from metron. So a measure together. There’s also metronome, a musical time keeper, which showed up in 1815. It’s not exactly from meter, instead taken directly from the Greek metron, with the addition of the PIE root nem-, assign, allot, or take.
 
Also from meter is semester, which didn’t show up until 1827 meaning a period of six months (it seemed a lot longer in school). It’s actually German in origin, though that was taken from the classical Latin semestris, from the phrase cursus semestris, a semester (or six month) course. That mestris is actually from mensis, month, which is from me-, but we’ll get more into that next week.
 
Finally today, commensurate. Which isn’t really used much these days, but means corresponding in magnitude. It showed up in the mid seventeenth century from the Late Latin commensuratus, which is a mix of the Latin com, together, and mensura, a measure. Commensurate is measuring together? Wait, isn’t that just symmetry?
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at San Antonio’s page on Proto Indo European language
Orbis Latinus