World: r3wp

It treats the series like sets. One of the group with UNIQUE.

and a diff should really show all points of difference

Divergence ?

so using 'diff implies more than one gets

( does 3 more characters add much ? )

It adds the right part of speech. Grammatical correctness.

if not diverge? seriesa seriesb [ print "they're equal mate!" ]

And it is more exactly on topic than difference or diff.

Divergence:  too obscure  a word  time to get the thesaurus... ;-)

shorter words are preferable too ... but who cares

It's an obscure meaning :) Shorter words are preferable as long as 
they mean the same thing.

sounds more like the title of a sci fi novel

But DIVERGE? is a way to add the equivalent meaning, but using REBOL 
naming conventions rather than English.

English doesn't have ? in words :)

I thought we were programming in rebol?

suffix?  length?

?  words are logic returning words.  true none false.

(at least that is what they should do.)

The base language for the naming of REBOL functions is English. But 
REBOL adds naming conventions that English doesn't have.

what logical computation does 'suffix? do ?

and length? et cetera

So the ? is the REBOL equivalent to the nce in divergence.

Otherwise, diverge is a verb.

? should stand for :

  is [something] ?

but its also used as:

  what is [something] ?


though the second form could be used on just about every function 
which isn't a process...  so I don't like that we sometimes add ? 
when we really are asking for a process of some data.

suffix?  is not does this have a suffix?  it's give me the suffix.

? is also used in Rebol to mean "of"

that is the second form..... 

 what is [something] of ?

of implied if there is an argumetn.

waste? [ of time ]

Then would need the nce. Diverge is still an action word. Divergence 
is the noun.

Sorry, language is defined by use ... not by dictionaries

Diverge is still a verb, and divergence still a nown. The dictionaries 
came later.

deviation

That would work. And it doesn't imply going in a different direction 
like diverge(nce) does.

Unless you go back to the latin, at which point both words have the 
same root: going in a different direction.

We have had to break out the thesaurus many times when naming REBOL 
functions :)

It's my #2 search link in my browser   ;-)

DIVERGENCE is a spot-on name.

Considering that it seems to return "the point of divergence", i.e. 
the position where two series start to diverge.

Native english speakers only please :)

(Says the guy who thinks "diverge" is a noune in usage ;-)

Sorry, bad typing day.

(Now my non-native brain gets confused: noun, nown, or noune? :)

noun. I have been doing manual labor and my hands are a little off 
today.

(http://www.urbandictionary.com/define.php?term=noune)

Nice :)

Maybe you accidentally offended Maxim :)

pronounced   noon

alternatives: fork, stray, deviate, digress

All verbs. Use the noun or adjectival forms.