noun, noun which may take the genitive case particle 'no'
fourth
Ordinal number; used as a noun or with の to modify another noun. Common in formal contexts, rankings, and numbered items.
彼は第四位に入賞した。
He won fourth place.
第四の選択肢を検討しよう。
Let's consider the fourth option.
More colloquial and concrete for 'the fourth one' in a sequence, while 第四 is more formal and often used in titles or numbered lists.
Compound of prefix 第 (ordinal marker) and 四 (four).