This is the 10182nd most frequent Japanese word.
鎖
"鎖" means "chain."
鎖 is used to denote a physical chain used for securing things.
この鎖でドアを固定してください。
Please secure the door with this chain.
鎖 is employed metaphorically to depict emotional or psychological constraints.
彼の孤独は心の鎖で縛られていた。
His loneliness was bound by chains of his heart.
鎖 forms compound word '鎖国' (sakoku) to express 'national isolation'.