This is the 8642nd most frequent Japanese word.
文久
"文久" (Bunkyū) refers to the Japanese era name spanning 1861–1864 during the late Edo period.
Here, '文久' is used as a specific era name within Japanese history.
文久年間は江戸時代の後期に属します。
The Bunkyū era belongs to the late Edo period.
In this sentence, '文久' is again functioning as a time period reference in historical context.
彼は文久年間に生まれました。
He was born during the Bunkyū era.
Here, '文久' describes the cultural aspects related to this historical era.