This is the 8227th most frequent Japanese word.
常磐
"常磐" (ときわ, Tokiwa) refers to something everlasting or evergreen, symbolizing permanence or continuity.
In this sentence, '常磐' is part of a proper noun referring to the 'Joban Line', which is a railway line in Japan.
常磐線に乗って東京まで行きます。
I will take the Joban Line to go to Tokyo.
Here, '常磐' is used as a poetic description meaning 'evergreen' or 'perpetually unchanging', often associated with nature.
常磐の松は一年中緑を保つ。
The evergreen pine trees retain their green color throughout the year.
In this context, '常磐地区' indicates a specific location or district named after 'Tokiwadai', demonstrating regional naming usage.