I am a linguist by nature and study. I have taken classes on English and its origins, I've taken 2 semesters of Japanese, I've taken 2 semesters of Spanish, and I know several other languages decent enough to converse.
As for the word anime, what I said up there is a fact, plain and simple. The history of the word, and what it means in other languages when used as a slang term. It's black and white. There is no room for "But I think it means this or this or something else other than what you said."
Of course, given that if used in our language, it is slang, interpretation is up to the speaker and the listener. Take the word "shit" for example. This slang term originally means the same thing as "feces". However, it's become much more versatile due to street use and interpretation over the years. Anime, being a slang term to those of us who speak English, is up for interpretation. And because this term is slang in our language, it doesn't really matter what a dictionary says about it.
Let's look at how
Merriam-Webster's Collegiate Dictionay defines the slang term "shit".
Main Entry: 1shit
Pronunciation: 'shit, interjectionally also 'shE-&t
Function: noun
Etymology: (assumed) Middle English, from Old English scite; akin to Old English -scItan to defecate
Date: circa 1585
1 usually vulgar : EXCREMENT
2 usually vulgar : an act of defecation
3 usually vulgar : NONSENSE, CRAP
4 usually vulgar : any of several intoxicating or narcotic drugs; especially : HEROIN
5 usually vulgar : DAMN 2
6 usually vulgar : a worthless, offensive, or detestable person
- shit·ty /'shi-tE/ adjective, usually vulgar
Notice anything missing? Plenty of meanings are missing in fact. shit can mean any of someone's possessions (I.E. I went out and bought some shit at the mall earlier.). Shit can mean to say that someone is lying. (I.E. "You're shitting me"). shit can mean food (I.E. That shit is good. (Derived from the definition referring to narcotics) ) etc...
I wonder what their definition of ANIME is.
Main Entry: an·i·me
Pronunciation: 'a-n&-"mA, 'ä-nE-
Function: noun
Etymology: Japanese, animation, short for animEshiyon, from English
Date: 1988
: a style of animation originating in Japan that is characterized by stark colorful graphics depicting vibrant characters in action-filled plots often with fantastic or futuristic themes
Though not incorrect, it is also incomplete. The date listed is when the word was put in the dictionary I imagine, since the tern "anime" is much older than that, even in the English Speaking world.
Again, slang terms are up for interpretation, so more or less having a set definition is a moot point. The definition I gave up there was more of a history of the word and its common uses than a set in stone definition, just like this entry in MWCD is not complete either.
But the fact remains that this word is slang, and is used in that way. Whether the dictionary contains a word is irrelevent.
And finally, one more definition for you all just for fun...
Main Entry: ain't
Pronunciation: 'Ant
Etymology: contraction of are not
Date: 1778
1 : am not : are not : is not
2 : have not : has not
3 : do not : does not : did not -- used in some varieties of Black English
usage Although widely disapproved as nonstandard and more common in the habitual speech of the less educated, ain't in senses 1 and 2 is flourishing in American English. It is used in both speech and writing to catch attention and to gain emphasis <the wackiness of movies, once so deliciously amusing, ain't funny anymore -- Richard Schickel> <I am telling you--there ain't going to be any blackmail -- R. M. Nixon>. It is used especially in journalistic prose as part of a consistently informal style <the creative process ain't easy -- Mike Royko>. This informal ain't is commonly distinguished from habitual ain't by its frequent occurrence in fixed constructions and phrases <well--class it ain't -- Cleveland Amory> <for money? say it ain't so, Jimmy! -- Andy Rooney> <you ain't seen nothing yet> <that ain't hay> <two out of three ain't bad> <if it ain't broke, don't fix it>. In fiction ain't is used for purposes of characterization; in familiar correspondence it tends to be the mark of a warm personal friendship. It is also used for metrical reasons in popular songs <Ain't She Sweet> <It Ain't Necessarily So>. Our evidence shows British use to be much the same as American.
Yep. Ain't is in the dictionary. That doesn't mean that your college composition teacher thinks it's okay that you use it.