> The clathrate’s “cage” shapes are 12-sided dodecahedrons and 14-sided tetrakaidecahedrons made of silicon atoms...
Totally OT but if "dodeca" means 12, why isn't 14 just "tetradeca"? What's the "kai" for?
Totally OT but if "dodeca" means 12, why isn't 14 just "tetradeca"? What's the "kai" for?
The correspondents of the -teen numbers in Greek were formed similarly with English, after the model of 14 = four and ten = "tetrakaideka".
"Tetrakaideka" is a contracted form of 14, normally used in compound words. When "14" was an isolated word, it would have been "tettarakaideka" or "tessarakaideka". These are the forms for the neuter gender, the numeral "4" = "tettara" or "tessara" (depending on the dialect) was changed by declension for other genders and cases.
In Ancient Greek numbers bigger than 20, the word "and" = "kai" was usually omitted, but then the bigger number was always the first like in "twenty-four". When "and" was inserted, then the order could also be inverse, like in "four-and-twenty".
I guess like asking why 120 is said "one hundred and twenty" in some dialects.
Maybe that's how 14 and 12 are written in Greek.
For example, already Aristotle used "dipoda" (2-feet) for humans and birds, "tetrapoda" (4-feet) for other terrestrial vertebrates and "hexapoda" (6-feet) for insects. After the same model one can say "oktopoda" (8-feet) about spiders and "tetrakaidekapoda" (14-feet) about woodlice.
"kai" is "and" in Greek.
:-)
I haven't read of any particular reason for this, but I'd posit that numbers up to twelve were more commonly used in everyday life, so shorter, irregular forms were easier to use and remember. Much like many of the irregular verb forms in spoken language happened because they were so commonly used.
The ancient Greek system also gave us triskaidekaphobia - the fear of the number 13.
There's also some fun when you get to 70... which is soixante-dix (sixty ten)... and 80 which is quatre-vingts (four twenties)... and 90 as quatre-vingt-dix (four twenties ten).
Some dialects of French outside of France have changed how they count.
18 is duodeviginti (two from twenty) and 19 is undeviginti (one from twenty).
But we do have duodecim, aka dozen. So we just need to add "onezen" to the current vernacular to make the set complete. Let's go team onezen!
12 being divisible by 2,3,4,6; 10 being divisible by 2,5 -- means base 12 is easier to multiply and divide to reach whole numbers.
Ancient Greek spans several centuries of sound shifts and many dialects. It cannot easily be simplified into one specific pronunciation, particularly not one that is based on your specific dialect of English. Wiktionary has /kǎi̯/, /ˈkɛ/, /ˈcɛ/ and /ˈce/ for "καὶ".