Why is distro, rather than distri, short for distribution in Linux world?
The OE has an extensive entry on the -o suffix ($) which I excerpt here:
The shortening of a word immediately after a medial o , and in particular where this occurs at the end of a prefix or combining form, first appears in the late 17th cent. and early 18th centuries, e.g. plenipo n., memo n., and hypo n.1 This probably established an association of the ending -o with casual or light-hearted use which it has retained ever since. Further examples are attested in the early 19th cent., e.g. (combining forms) Anglo n.1, mezzo n.1, typo n.; (other words) compo n.2, loco n.1 After 1851 this type of clipping becomes, and has remained, extremely common.
The pronunciation of "distribution" is:
dis·tri·bu·tion — [dis-truh-byoo-shuhn] — /ˌdɪstrəˈbyuʃən/
"-stri" would typically be pronounced similar to the beginning of "street" or "stripe".
"-stro", on the other hand, would be pronounced similar to the beginning of "strobe" which isn't exactly the same but close enough in American English that we'd rather say "distro" than "distri".
If you create a new word, similarity to already existing words makes the difference between "sound good" and "sound weird".
"Distro" is very similar to already existing word "bistro". There are also "maestro", "electro", "nitro", "metro", "retro" etc.
On the other hand, I don't know any word with singular ending with "-tri". It looks like some plural form (like "uteri").
An abbreviation doesn't have to use an unbroken sequence of letters beginning with the start of the word, so "DISTRibutiOn" can collapse to "distro".
What does "Linux" itself stand for if not "LINUs' (variant of) uniX"?
At the risk of triggering Godwin's Law, there is the rather (in)famous example of "NAtionalsoZIalistische".
Uh, because distro sounds awesome...
Distri sounds like a New Yorker pointing out which bit of flora you want duh gahdnuh (gardener) to cut down. [Dis tree . . . as opposed to dat tree.]
And before anyone complains that is a Boston accent: Gawdnuh is Boston. Gahdnuh is New York. I'll let @RegDwigнt translate that into IPA for anyone who wishes. ;-)
Because the i in "distri" would be short, and awkward.
In English when you have a vowel sound followed by a consonant, the syllable break is generally between them for long vowels, and after them for short vowels.
Consider: pro/nounce or ma/king, vs. pub/lic or but/ton.
Consequently, we don't really have dangling short vowels very often - at the end of words or anywhere else.
Distro is slang. One usage example is http://distrowatch.com. And if you google for distribution etymology, you get the following diagram.
Latin: distribuere -> distributio
English: distribute -> distribution
If you pronounce distribution in English, it sounds like distribjuschen (http://dictionary.cambridge.org/us/pronunciation/business-english/distribution).
But Linux and many open source distributions come from Europe. And this term could have been coined in Germany where distribution is pronounced differently (http://de.wiktionary.org/wiki/Distribution, no voice recording).
In the English distribution, only the first two syllables are strong (distri); the bution follows after like a tail. But in the German distribution, the dis is strong, the tri is fairly weak, the bu is strong and the tion again is strong: DIStriBUtiON vs DISTRIbution.
So from the English pronunciation, going to distri is most logical. In German however the tri is weak so going to distri makes no phonetic sense.