Used to introduce a name, quote, or label (e.g., 'called', 'that is said'); often written in kana.
彼は田中という人です。
He is a person called Tanaka.
「成功」という言葉は人によって意味が違う。
The word 'success' means different things to different people.
あの店は「ラーメンの名店」という評判だ。
That shop has a reputation as a 'famous ramen place.'
Placed after a quantity to emphasize its size or extent (meaning 'as many as' or 'as much as').
参加者は100人という多さに驚いた。
They were surprised by how many participants there were — as many as 100 people.
1時間という短い時間で彼は仕事を片付けた。
He finished the work in the short time of one hour.
値段は1万円という高額だった。
The price was a high amount — as much as 10,000 yen.
In patterns like 'AというA', it means 'all A' or 'every single A' (i.e., every one of that group).
子供という子供がみな泣いていた。
Every child there was crying.
学生という学生は試験会場に集められた。
Every single student was gathered in the exam hall.