Denshi Jisho — Online Japanese dictionary

を 1: indicates direct object of action;
2: indicates subject of causative expression;
3: indicates an area traversed;
4: indicates time (period) over which action takes place;
5: indicates point of departure or separation of action;
6: indicates object of desire, like, hate, etc.
Common word, Particle 
ヲタ nerd; geek; enthusiast
Noun, Suffix, Colloquialism, Abbreviation 
をば marks object of action, etc. (also adds emphasis)
Particle, Archaism 
ヲタク geek; nerd; enthusiast; otaku
Irregular kana usage, Noun, Colloquialism 
ヲッカ vodka
Noun, rus: 
ヲタ車 ヲタしゃ otaku car (painted with anime characters, loaded with figures and stuffed dolls, etc.)
Noun, Colloquialism 
ヲコト点 ヲコトてん marks to aid in reading Chinese classics
Noun 
乎古止点 をことてん marks to aid in reading Chinese classics
Noun 
乎己止点 をことてん marks to aid in reading Chinese classics
Noun 
遠古登点 をことてん marks to aid in reading Chinese classics
Noun 
を経て をへて via; passing through
Expression 
を以て をもって by (means of); with
Adverb, Usually written using kana alone 
を措いて をおいて other than; excluding; without
Expression, Usually written using kana alone 
を以って をもって by (means of); with
Adverb, Usually written using kana alone 
を介して をかいして using as an intermediary; through
Expression 
を限りに をかぎりに as of the end of (today, this month, etc.); to make (today, etc.) the last (day)
Expression 
を通して をとおして through; throughout; through (the good offices of); by way of
Expression 
を回って をめぐって in regard to; concerning (usu. of disputes)
Expression 
を巡って をめぐって in regard to; concerning (usu. of disputes)
Expression 
を廻って をめぐって in regard to; concerning (usu. of disputes)
Expression 
を元として をもととして based on; built on; made from
Expression 
を基として をもととして based on; built on; made from
Expression 
を元にして をもとにして based on; built on; made from
Expression 
を基にして をもとにして based on; built on; made from
Expression 
を単位として をたんいとして in increments of
Expression, Computer terminology 

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