Rebol's historical leaning was to give things "plain names", even when that ran counter to computing tradition.
(For instance DECIMAL! was called that instead of what it really was... a FLOAT!, because "floating point" is too techie a concept. Yet "decimal" means a different type of numeric representation underlying the math. Red reversed this decision, and calls floating point numbers FLOAT!)
There has been rough consensus that MAP should be a verb, for applying an operation across a data structure.
To recap, with Ren-C's concept of generators, we could make a generator called EACH
>> gen: each [1 2]
>> gen
== 1
>> gen
== 2
>> gen
; null
And then we've talked about how FOR would call the generator repeatedly until it hit NULL, returning the last body result:
>> for x each [1 2] [print [x], x * 10]
1
2
== 20
So MAP has been suggested as being the version that collects the body results as you go:
>> map x each [1 2] [print [x], x * 10]
== [10 20]
Seems pretty neat and composable, huh?
But this makes it feel like calling a datatype MAP! just muddles things.
DICTIONARY! is a bit long to write out, but... people seemed to tolerate "refinement". Same number of letters (and wider in a non-fixed width font...)
DICTIONARY!
REFINEMENT!
DICTIONARY
REFINEMENT
...so dictionary doesn't really seem so bad, if you ask me.