noun, noun which may take the genitive case particle 'no'
fifth
Ordinal number used in formal or systematic contexts, such as rankings, chapters, or numbered items. Often followed by a noun with の.
彼は第五位に入賞した。
He won fifth place.
第五の選択肢を選んでください。
Please choose the fifth option.
More colloquial and common in everyday speech for 'fifth' in a sequence, while 第五 is more formal or systematic.
Compound of 第 (ordinal prefix) and 五 (five), following the standard pattern for ordinal numbers in Japanese.