Classics 22: Etymology

• The Greek letter ξ  Ξ
  
• Called "Xi"
  
• Pronounced /ksee/
• Transliterated by x.
• Unlike other Greek letters, ξ  Ξ  does not correspond to one single sound phoneme. ξ  Ξ is actually two phonemes put together.
  
• The first phoneme is the sound /k/
• But as we will see, behind that /k/ may lie a gamma, a kappa, or a chi.
  
• The second phoneme is always the sound /s/, Greek ς (sigma)
• There are many nouns in Greek that end in ξ  Ξ. Many of them are English words too. Consider the following three in particular:
• coccyx (a technical term for your buttbone)
  
• anthrax (Greek for "coal" or "zit": English for a disease that has zit-like eruptions as a symptom)
  
• onyx (Greek for "toenail," "fingernail" or "claw": English for a kind of stone.
  
• Those three are English words, but they also occur compounded with other elements:
• coccygodynia (pain in the butt)
• anthracite (a kind of coal)
•  onychophagia (pathological nail-biting)
• Note that when those roots combined with other roots after them, those three roots lost the sibilant part of their ξ. In other words, they lost their ς (sigma).  Once the sigma drops out, one of three Greek letters is left:
  
• γ (gamma) transliterated g
• κ (kappa) transliterated k or c
• χ (chi) transliterated ch
• The upshot of all that is that : Greek nouns whose nominatives end in ξ  drop the ς , which  makes the end of the stem revert to  γ, κ, or χ, as the endings of the stems in the following table illustrates.