固有関数: eigenfunction

a type of military boat used between the Warring States Period and the Edo Era

(historical) a mountain checkpoint west of Kyoto, bordering the ancient provinces of Yamashiro and Omi

Shanhai Pass

Synonym of 関東 (Kantō): the area east of 逢坂の関 (Ōsaka-no-seki, “tollgate of Ōsaka-yama”) or the 函谷関 (Kankoku-kan, “Hangu Pass”)

the lock and key for a gate

to close and lock a gate

考え: thought, opinion

図鑑: An illustrated reference book, such as a field guide, bestiary, guide book, or picture book

監視網: surveillance network