What is the meaning of う?

The hiragana syllable う (u). Its equivalent in katakana is ウ (u). It is the third syllable in the gojūon order; its position is あ行う段 (a-gyō u-dan, “row a, section u”).

expressing one's will to do something

inducing or stimulating another person to do something

to try to do, to attempt to do

to be about to do; to be on the verge of doing

presenting a supposition

whether … or …

alternative form of く (-ku, adverbial suffix of -i adjectives)

1. used to respectfully refer to something that belongs to or is related to the listener or a third party

used to respectfully refer to something that belongs to or is related to the listener or a third party

Source: wiktionary.org