noun, noun which may take the genitive case particle 'no'
number one; first; first place
Literal rank, order, or position: No. 1, first in a sequence, or first place in a competition. As 一番の, it can modify another noun.
彼女は大会で一番になった。
She came in first in the tournament.
一
Please enter starting with the person holding the number-one ticket.
adverb
Adverbial superlative meaning 'the most' or 'the best' among a set; very common before adjectives, adjectival nouns, and verbs of liking or preference.
この店のラーメンが一番好きです。
I like this shop's ramen the best.
朝が一番涼しい。
It is coolest in the morning.
noun
A noun for a single match, round, or bout, often in set collocations such as 相撲を一番取る or 勝負を一番する. More limited than the everyday rank/superlative senses.
稽古で先輩と相撲を一番取った。
I had one sumo bout with a senior during practice.
adverb
as a test; by way of trial; tentatively
Idiomatic adverbial use meaning 'just to try it' or 'as an experiment,' often in phrases like 一番やってみる. Modern Japanese more often uses 試しに or ひとつ for this idea.
See also: 試しに
うまくいくか分からないが、一番やってみよう。
I don't know whether it will work, but let's give it a try.
noun
Specialized use for a song or piece, especially in contexts such as noh chanting. It is not the ordinary everyday word for a song.
能楽の会で、謡を一番うたった。
At the noh performance gathering, I sang one chant piece.