Jisho

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Auxiliary verb
1. indicates speculationafter the imperfective form of certain verbs and adjectives
Auxiliary verb
2. indicates will
Auxiliary verb
3. indicates invitation
Wikipedia definition
4. U (kana)う in hiragana or ウ in katakana is one of the Japanese kana, each of which represents one mora. In the modern Japanese system of alphabetical order, they occupy the third place in the modern Gojūon (五十音) system of collating kana. In the Iroha, they occupied the 24th position, between む and ゐ. In the Gojūon chart (ordered by columns, from right to left), う lies in the first column (あ行, "column A") and the third row (う段, "row U"). Both represent the sound [u͍ u͍].
Read “U (kana)” on English Wikipedia
Read “う” on Japanese Wikipedia
Read “U (kana)” on DBpedia

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