1. Noun which may take the genitive case particle 'no', Noun

   1.

   first; foremost; number one

2. 2.

   most important

3. 3.

   best; greatest; most

Example sentences

• 安全が第一だよ。

  Safety is the most important thing.

• 第一印象は大切だ。

  First impressions are important.