The term "otaku" seems to have been introduced to anime fans in the US and other countries via Studio Gainax's "Otaku no Video 1985," a self-parody film.
Otaku, meaning probably "venerable house," refers to someone who has a devotion to a subject or hobby (not necessarily anime) to the point of not leaving home. For instance, an otaku fan of a particular movie star could quite possibly know all of the films s/he has been in, their birth date, time of birth, shoe size, favorite toothpaste, etc. Generally speaking, calling someone an otaku in Japan is an insult, implying that their social skills have atrophied or never even developed, due to their manic involvement in their chosen fandom.

In America, the term is used to denote a zealous fan, usually of anime and/or manga. Due to its introduction to most people's vocabulary through its tongue-in-cheek use in Gainax's film, "otaku" tends to have a much less dire definition overseas.

When dealing with Japanese people, however, it may be best to keep in mind the modern Japanese image of an otaku -- Someone who only leaves their home to eat or shop, if at all, with an overwhelming and unhealthy obsession about something. It can as easily refer to a stalker or sociopath as it can to a harmless anime buff.

Best to avoid the word altogether if one is not sure of the context in which it will be received.
Positive: "Oh, wow! Check it out: Neck-through, Floyd Rose locking tremolo and an optional push/pull coil tap!" (slaps forehead and laughs) "Man, I am such a guitar otaku, aren't I?"

Negative: "Stay clear of Toshi, man. He's such a RQ otaku, always online. Bet he's never actually even talked to a real-live girl before... You never know when he's gonna' snap, right?"
by Cobweb February 24, 2005
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A life form that dies if it cannot watch anime
My roommate's a complete otaku and cried for a week because Naruto was over
by epic_pandemic December 19, 2014
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Originally the Japanese term for "house (more specifically, your house" in the honorific form of the language, made by adding the prefix "o-" to the word for house "taku." It can also be used as an honorific second-person pronoun.

Today, the word has taken on a different meaning: it refers to a person who has had or is in the middle of having an intense hobby, which is usually added before the word itself. See the example below (1).

The connotation of the term varies in relation to the speaker and how much said speaker knows about the actual context in which it should be used. Especially common among American fans, an otaku is simply a very devoted follower (2). However, the word has a harsher, more negative connotation in Japanese. It is a term that refers to the receiver of the description is a very reclusive, sociopathic person who has a severe addiction to any form of media and (in some cases) will rarely, if ever, leave his or her house to meet minimal living requirements or obtain more of said media (hence the term otaku derived from its original meaning refering to a house)(3). It is not to be confused with the term "hikikomori," or a person/people who has/have withdrawn from society. It is a dire insult, especially to those who do not actually fit the category of otaku.

Otaku (plural) are generally looked down upon in Japanese society, constantly derided for their passions. These insults may or may not have a penny's worth of truth, but they base themselves in preconceived notions of how previous people of obsession have acted. The otaku do receive a lot of scorn from their fellow peers, and hate crimes against them are not all that uncommon (4). Nevertheless, the word is not completely negative. For example, the largest anime/manga/East Asian convention in the United States is named "Otakon", and there is also the American-based "A-kon" (5). Several people worldwide have made attempts to remove its negative connotation, but have not been completely successful.
(1) Coinage
anime otaku, manga otaku

(2) American Usage, two boys
"I haven't left my room for days, I'm totally addicted to One Piece."
"Dude, you're a total otaku."
"Yeah, right?"

(3) Japanese Usage, one girl approaching a boy; the girl is stopped by a group of her peers who reprimand her advance
"Hey, you might want to stay away from that guy. He's an otaku."
(This comment is usually followed by sounds and/or remarks made by the new girl and/or the group itself.)
"Like the hikikomori type?"
"Nah, he actually leaves his house to buy groceries."

(4) Mention of hate crimes against said person/people
"In 1989, a man named Tsutomu Miyazaki became known as 'The Otaku Murderer' for his crimes which specifically targeted otaku."

(5) Two people mentioning Otakon
"Hey, are you goin' to Otakon this weekend?"
"Hell yeah, I'mma be outa money by Sunday! You?"
"Wish. I gotta lot of make-up work for 'being sick' during that last convention."
by Flashtirade February 10, 2009
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My definition, which was correct was removed by biased peoples. Oh well. Here I go again.

In Japan the word Otaku is a label that is quite bad. Most Japanese people would not want to be considered an otaku.
In America, however, we have morphed the word as we always do to our own meaning. There is nothing wrong with this. Over in America it means "to be a big fan of", and really doesn't have a bad meaning, as it would in Japan.

As such, you wouldn't want to go to Japan and start saying how much of an Otaku you are. In America this is fine, and probably in Canada as well. However, alot of people here seem to forget that they are saying what the Japanese interpret it as. Most people that read this hail from North America where the definition has a fairly benign meaning.

I rest my case.
Japan: Ugh, he's so disgusting... must be a anime otaku.

North America: Dude, you are totally a hardcore Otaku!
by brian clemens February 9, 2005
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Otaku has multiple meanings. Casual anime fans use this word in the context of being a well established fan who knows much about anime and manga. Japanese see this term as derogitory which represents a person who is a lifeless nerd. Wapanese see this as derogitory given their strong beilief that because they watched some anime that all the sudden they are japanese.
This is a high-context word, in the american dialect, given the type of people using the word and the context of the discussion this OTAKU could mean expert or geek, complemetary or derogatory.
Larry has a wealth of knowlege about anime, he is a real otaku.
by Tabenokoshi December 28, 2004
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A Japanese word describing a person beyond the realm of fandom but into mania that is improperly used by American fans.

In Japan the word "otaku" has become taboo because of Miyazaki Tsutomu who went on a toddler murdering spree in the 80's, video taping the young girls he had murdered from an obsession with lolicon (female pedophilic manga).

Americans use this term to call themselves "fanboys" or "fangirls" with almost no knowledge of the horrific roots behind the word.
American Fangirl: "I have a huge collection of Macross, NGE, Sailor Moon, yaoi, and many other anime! I'm such an otaku!"
Non-anime fan: "...Uhm, you do know about that word right?"
by Erin December 19, 2003
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In American culture, 'Otaku' means 'One who is obsessed with Japanese culture, entertainment, etc.'

It literally is the honorific way to say 'House', and is used to mean 'Someone who stays in their house all the time'.

It's not usually a good thing to be called an Otaku, but others take pride in it.
Person 1: I love anime!
Person 2: You're such an Otaku!
by Darkinuhanyou September 1, 2006
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